Update internal links and anchors in API docs

Internal links have been changed to relative URLs. This should help with redirecting to translated pages (the URL won't have to be localized) and keeping the right version.
Anchors that point to headers that are localized will have to be changed.

Author: krzysdz

src/content/api/3x/api/request/index.mdx

@@ -164,7 +164,7 @@ where "proxy2" is the furthest down-stream.
 This property is much like `req.url`, however it retains
 the original request url, allowing you to rewrite `req.url`
 freely for internal routing purposes. For example the "mounting" feature
-of <a href="#app.use">app.use()</a> will rewrite `req.url` to
+of [app.use()](../application/#appusepath-function) will rewrite `req.url` to
 strip the mount point.
 
 ```js
@@ -243,7 +243,7 @@ console.dir(req.query.shoe.type);
 
 ### req.res
 
-This property holds a reference to the <a href="#response">response object</a>
+This property holds a reference to the [response object](../response/)
 that relates to this request object.
 
 ### req.route

src/content/api/3x/api/response/index.mdx

@@ -24,7 +24,7 @@ res.send('<p>some html</p>');
 
 Response local variables are scoped to the request, thus only
 available to the view(s) rendered during that request / response
-cycle, if any. Otherwise this API is identical to <a href="#app.locals">app.locals</a>.
+cycle, if any. Otherwise this API is identical to [app.locals](../application/#applocals).
 
 This object is useful for exposing request-level information such as the
 request pathname, authenticated user, user settings etcetera.
@@ -39,7 +39,7 @@ app.use(function (req, res, next) {
 
 ### res.req
 
-This property holds a reference to the <a href="#request">request object</a>
+This property holds a reference to the [request object](../request/)
 that relates to this response object.
 
 ## Methods
@@ -106,7 +106,7 @@ to sign the value.
 res.cookie('name', 'tobi', { signed: true });
 ```
 
-Later you may access this value through the <a href="#req.signedCookies">req.signedCookie</a>
+Later you may access this value through the [req.signedCookie](../request/#reqsignedcookies)
 object.
 
 ### res.download(path, [filename], [fn])
@@ -230,7 +230,7 @@ res.jsonp(500, { error: 'message' });
 ```
 
 By default the JSONP callback name is simply `callback`,
-however you may alter this with the <a href="#app-settings">jsonp callback name</a>
+however you may alter this with the [jsonp callback name](../application/#settings)
 setting. The following are some examples of JSONP responses using the same
 code:
 

src/content/api/4x/api/application/index.mdx

@@ -20,7 +20,7 @@ var app = express();
 
 This is a built-in middleware function in Express. It parses incoming requests
 with JSON payloads and is based on
-[body-parser](/en/resources/middleware/body-parser).
+[body-parser](../../../resources/middleware/body-parser).
 
 Returns middleware that only parses JSON and only looks at requests where
 the `Content-Type` header matches the `type` option. This parser accepts any
@@ -62,7 +62,7 @@ The following table describes the properties of the optional `options` object.
 
 This is a built-in middleware function in Express. It parses incoming request
 payloads into a `Buffer` and is based on
-[body-parser](/en/resources/middleware/body-parser).
+[body-parser](../../../resources/middleware/body-parser).
 
 Returns middleware that parses all bodies as a `Buffer` and only looks at requests
 where the `Content-Type` header matches the `type` option. This parser accepts
@@ -98,7 +98,7 @@ The following table describes the properties of the optional `options` object.
 
 ### express.Router([options])
 
-Creates a new [router](#router) object.
+Creates a new [router](../router/) object.
 
 ```js
 var router = express.Router([options]);
@@ -119,17 +119,17 @@ The optional `options` parameter specifies the behavior of the router.
 You can add middleware and HTTP method routes (such as `get`, `put`, `post`, and
 so on) to `router` just like an application.
 
-For more information, see [Router](#router).
+For more information, see [Router](../router/).
 
 ### express.static(root, [options])
 
 This is a built-in middleware function in Express.
-It serves static files and is based on [serve-static](/en/resources/middleware/serve-static).
+It serves static files and is based on [serve-static](../../../resources/middleware/serve-static).
 
 <Alert type="info">
 
 For best results, [use a reverse
-proxy](/en/advanced/best-practice-performance#use-a-reverse-proxy) cache to improve performance of
+proxy](../../../advanced/best-practice-performance#use-a-reverse-proxy) cache to improve performance of
 serving static assets.
 
 </Alert>
@@ -161,8 +161,8 @@ See also the [example below](#example-of-expressstatic).
 
 </div>
 
-For more information, see [Serving static files in Express](/en/starter/static-files).
-and [Using middleware - Built-in middleware](/en/guide/using-middleware#middleware.built-in).
+For more information, see [Serving static files in Express](../../starter/static-files).
+and [Using middleware - Built-in middleware](../../guide/using-middleware/#built-in-middleware).
 
 #### dotfiles
 
@@ -198,7 +198,7 @@ fn(res, path, stat);
 
 Arguments:
 
-- `res`, the [response object](#res).
+- `res`, the [response object](../response/).
 - `path`, the file path that is being sent.
 - `stat`, the `stat` object of the file that is being sent.
 
@@ -228,7 +228,7 @@ app.use(express.static('public', options));
 
 This is a built-in middleware function in Express. It parses incoming request
 payloads into a string and is based on
-[body-parser](/en/resources/middleware/body-parser).
+[body-parser](../../../resources/middleware/body-parser).
 
 Returns middleware that parses all bodies as a string and only looks at requests
 where the `Content-Type` header matches the `type` option. This parser accepts
@@ -268,7 +268,7 @@ The following table describes the properties of the optional `options` object.
 <Alert type="info">This middleware is available in Express v4.16.0 onwards.</Alert>
 
 This is a built-in middleware function in Express. It parses incoming requests
-with urlencoded payloads and is based on [body-parser](/en/resources/middleware/body-parser).
+with urlencoded payloads and is based on [body-parser](../../../resources/middleware/body-parser).
 
 Returns middleware that only parses urlencoded bodies and only looks at
 requests where the `Content-Type` header matches the `type` option. This

src/content/api/4x/api/express/index.mdx

@@ -67,7 +67,7 @@ module.exports = function (req, res) {
 
 The URL path on which a router instance was mounted.
 
-The `req.baseUrl` property is similar to the [mountpath](#app.mountpath) property of the `app` object,
+The `req.baseUrl` property is similar to the [mountpath](../application/#appmountpath) property of the `app` object,
 except `app.mountpath` returns the matched path pattern(s).
 
 For example:
@@ -98,7 +98,7 @@ made to `/hello/jp`, `req.baseUrl` is "/hello".
 
 Contains key-value pairs of data submitted in the request body.
 By default, it is `undefined`, and is populated when you use body-parsing middleware such
-as [`express.json()`](#express.json) or [`express.urlencoded()`](#express.urlencoded).
+as [`express.json()`](../express/#expressjsonoptions) or [`express.urlencoded()`](../express/#expressurlencodedoptions).
 
 <Alert type="warning">
 
@@ -158,7 +158,7 @@ console.dir(req.fresh);
 
 Contains the hostname derived from the `Host` HTTP header.
 
-When the [`trust proxy` setting](/en/4x/api#trust.proxy.options.table)
+When the [`trust proxy` setting](../application/#options-for-trust-proxy-setting)
 does not evaluate to `false`, this property will instead get the value
 from the `X-Forwarded-Host` header field. This header can be set by
 the client or by the proxy.
@@ -184,7 +184,7 @@ console.dir(req.hostname);
 
 Contains the remote IP address of the request.
 
-When the [`trust proxy` setting](/en/4x/api#trust.proxy.options.table) does not evaluate to `false`,
+When the [`trust proxy` setting](../application/#options-for-trust-proxy-setting) does not evaluate to `false`,
 the value of this property is derived from the left-most entry in the
 `X-Forwarded-For` header. This header can be set by the client or by the proxy.
 
@@ -195,7 +195,7 @@ console.dir(req.ip);
 
 ### req.ips
 
-When the [`trust proxy` setting](/en/4x/api#trust.proxy.options.table) does not evaluate to `false`,
+When the [`trust proxy` setting](../application/#options-for-trust-proxy-setting) does not evaluate to `false`,
 this property contains an array of IP addresses
 specified in the `X-Forwarded-For` request header. Otherwise, it contains an
 empty array. This header can be set by the client or by the proxy.
@@ -219,7 +219,7 @@ module](https://nodejs.org/api/http.html#http_message_url).
 
 This property is much like `req.url`; however, it retains the original request URL,
 allowing you to rewrite `req.url` freely for internal routing purposes. For example,
-the "mounting" feature of [app.use()](#app.use) will rewrite `req.url` to strip the mount point.
+the "mounting" feature of [app.use()](../application/#appusepath-callback--callback) will rewrite `req.url` to strip the mount point.
 
 ```js
 // GET /search?q=something
@@ -242,7 +242,7 @@ app.use('/admin', function (req, res, next) {
 
 ### req.params
 
-This property is an object containing properties mapped to the [named route "parameters"](/en/guide/routing#route-parameters). For example, if you have the route `/user/:name`, then the "name" property is available as `req.params.name`. This object defaults to `{}`.
+This property is an object containing properties mapped to the [named route "parameters"](../../guide/routing/#route-parameters). For example, if you have the route `/user/:name`, then the "name" property is available as `req.params.name`. This object defaults to `{}`.
 
 ```js
 // GET /user/tj
@@ -260,7 +260,7 @@ console.dir(req.params[0]);
 
 Named capturing groups in regular expressions behave like named route parameters. For example the group from `/^\/file\/(?<path>.*)$/` expression is available as `req.params.path`.
 
-If you need to make changes to a key in `req.params`, use the [app.param](/en/4x/api#app.param) handler. Changes are applicable only to [parameters](/en/guide/routing#route-parameters) already defined in the route path.
+If you need to make changes to a key in `req.params`, use the [app.param](../application/#appparamname-callback) handler. Changes are applicable only to [parameters](../../guide/routing/#route-parameters) already defined in the route path.
 
 Any changes made to the `req.params` object in a middleware or route handler will be reset.
 
@@ -283,15 +283,15 @@ console.dir(req.path);
 <Alert type="info">
 
 When called from a middleware, the mount point is not included in `req.path`. See
-[app.use()](/en/4x/api#app.use) for more details.
+[app.use()](../application/#appusepath-callback--callback) for more details.
 
 </Alert>
 
 ### req.protocol
 
 Contains the request protocol string: either `http` or (for TLS requests) `https`.
 
-When the [`trust proxy` setting](#trust.proxy.options.table) does not evaluate to `false`,
+When the [`trust proxy` setting](../application/#options-for-trust-proxy-setting) does not evaluate to `false`,
 this property will use the value of the `X-Forwarded-Proto` header field if present.
 This header can be set by the client or by the proxy.
 
@@ -303,7 +303,7 @@ console.dir(req.protocol);
 ### req.query
 
 This property is an object containing a property for each query string parameter in the route.
-When [query parser](/en/api/application/app-set#app.settings.table) is set to disabled, it is an empty object `{}`, otherwise it is the result of the configured query parser.
+When [query parser](../application/#application-settings) is set to disabled, it is an empty object `{}`, otherwise it is the result of the configured query parser.
 
 <Alert type="warning">
 
@@ -314,7 +314,7 @@ may not be a function and instead a string or other user-input.
 
 </Alert>
 
-The value of this property can be configured with the [query parser application setting](/en/api/application/app-set#app.settings.table) to work how your application needs it. A very popular query string parser is the [`qs` module](https://www.npmjs.org/package/qs), and this is used by default. The `qs` module is very configurable with many settings, and it may be desirable to use different settings than the default to populate `req.query`:
+The value of this property can be configured with the [query parser application setting](../application/#application-settings) to work how your application needs it. A very popular query string parser is the [`qs` module](https://www.npmjs.org/package/qs), and this is used by default. The `qs` module is very configurable with many settings, and it may be desirable to use different settings than the default to populate `req.query`:
 
 ```js
 var qs = require('qs');
@@ -325,11 +325,11 @@ app.set('query parser', function (str) {
 });
 ```
 
-Check out the [query parser application setting](/en/api/application/app-set#app.settings.table) documentation for other customization options.
+Check out the [query parser application setting](../application/#application-settings) documentation for other customization options.
 
 ### req.res
 
-This property holds a reference to the <a href="#res">response object</a>
+This property holds a reference to the [response object](../response)
 that relates to this request object.
 
 ### req.route
@@ -407,7 +407,7 @@ console.dir(req.subdomains);
 
 The application property `subdomain offset`, which defaults to 2, is used for determining the
 beginning of the subdomain segments. To change this behavior, change its value
-using [app.set](/en/4x/api#app.set).
+using [app.set](../application/#appsetname-value).
 
 ### req.xhr
 

src/content/api/4x/api/request/index.mdx

@@ -36,7 +36,7 @@ and supports all [built-in fields and methods](https://nodejs.org/api/http.html#
 
 This property holds a reference to the instance of the Express application that is using the middleware.
 
-`res.app` is identical to the [req.app](#req.app) property in the request object.
+`res.app` is identical to the [req.app](../request/#reqapp) property in the request object.
 
 ### res.headersSent
 
@@ -52,7 +52,7 @@ app.get('/', function (req, res) {
 
 ### res.locals
 
-Use this property to set variables accessible in templates rendered with [res.render](#resrenderview-locals-callback).
+Use this property to set variables accessible in templates rendered with [res.render](#resrenderview--locals--callback).
 The variables set on `res.locals` are available within a single request-response cycle, and will not
 be shared between requests.
 
@@ -66,7 +66,7 @@ for the used view engine for additional considerations.
 </Alert>
 
 In order to keep local variables for use in template rendering between requests, use
-[app.locals](#app.locals) instead.
+[app.locals](../application/#applocals) instead.
 
 This property is useful for exposing request-level information such as the request path name,
 authenticated user, user settings, and so on to templates rendered within the application.
@@ -82,7 +82,7 @@ app.use(function (req, res, next) {
 
 ### res.req
 
-This property holds a reference to the <a href="#req">request object</a>
+This property holds a reference to the [request object](../request/)
 that relates to this response object.
 
 ## Methods
@@ -238,7 +238,7 @@ Then `res.cookie()` will use the secret passed to `cookieParser(secret)` to sign
 res.cookie('name', 'tobi', { signed: true });
 ```
 
-Later you may access this value through the [req.signedCookie](#req.signedCookies) object.
+Later you may access this value through the [req.signedCookie](../request/#reqsignedcookies) object.
 
 ### res.download(path [, filename] [, options] [, fn])
 
@@ -310,7 +310,7 @@ res.status(404).end();
 ### res.format(object)
 
 Performs content-negotiation on the `Accept` HTTP header on the request object, when present.
-It uses [req.accepts()](#req.accepts) to select a handler for the request, based on the acceptable
+It uses [req.accepts()](../request/#reqacceptstypes) to select a handler for the request, based on the acceptable
 types ordered by their quality values. If the header is not specified, the first callback is invoked.
 When no match is found, the server responds with 406 "Not Acceptable", or invokes the `default` callback.
 
@@ -402,7 +402,7 @@ res.status(500).jsonp({ error: 'message' });
 
 By default, the JSONP callback name is simply `callback`. Override this with the
 
-<a href="/api/application/app-settings/">jsonp callback name</a> setting.
+[jsonp callback name](../application/#application-settings) setting.
 
 The following are some examples of JSONP responses using the same code:
 
@@ -458,7 +458,7 @@ res.location('back');
 A `path` value of "back" has a special meaning, it refers to the URL specified in the `Referer` header of the request. If the `Referer` header was not specified, it refers to "/".
 
 See also [Security best practices: Prevent open redirect
-vulnerabilities](http://expressjs.com/en/advanced/best-practice-security#prevent-open-redirects).
+vulnerabilities](../../../advanced/best-practice-security/#prevent-open-redirects).
 
 <Alert type="warning">
 After encoding the URL, if not encoded already, Express passes the specified URL to the browser in the `Location` header,
@@ -532,7 +532,7 @@ res.redirect('back');
 </Alert>
 
 See also [Security best practices: Prevent open redirect
-vulnerabilities](http://expressjs.com/en/advanced/best-practice-security#prevent-open-redirects).
+vulnerabilities](../../../advanced/best-practice-security/#prevent-open-redirects).
 
 ### res.render(view [, locals] [, callback])
 
@@ -544,7 +544,7 @@ Optional parameters:
 
 The `view` argument is a string that is the file path of the view file to render. This can be an absolute path, or a path relative to the `views` setting. If the path does not contain a file extension, then the `view engine` setting determines the file extension. If the path does contain a file extension, then Express will load the module for the specified template engine (via `require()`) and render it using the loaded module's `__express` function.
 
-For more information, see [Using template engines with Express](/en/guide/using-template-engines).
+For more information, see [Using template engines with Express](../../guide/using-template-engines).
 
 <Alert type="warning">
 

src/content/api/4x/api/response/index.mdx

@@ -10,9 +10,9 @@ as a "mini-application," capable only of performing middleware and routing
 functions. Every Express application has a built-in app router.
 
 A router behaves like middleware itself, so you can use it as an argument to
-[app.use()](/en/4x/api/application#appusepath-callback--callback) or as the argument to another router's [use()](#routerusepath-function--function) method.
+[app.use()](../application#appusepath-callback--callback) or as the argument to another router's [use()](#routerusepath-function--function) method.
 
-The top-level `express` object has a [Router()](/en/4x/api/express#expressrouteroptions) method that creates a new `router` object.
+The top-level `express` object has a [Router()](../express#expressrouteroptions) method that creates a new `router` object.
 
 Once you've created a router object, you can add middleware and HTTP method routes (such as `get`, `put`, `post`,
 and so on) to it just like an application. For example:
@@ -306,8 +306,8 @@ belong to the route to which they were added.
 
 Uses the specified middleware function or functions, with optional mount path `path`, that defaults to "/".
 
-This method is similar to [app.use()](/en/4x/api/application#appusepath-callback--callback). A simple example and use case is described below.
-See [app.use()](/en/4x/api/application#appusepath-callback--callback) for more information.
+This method is similar to [app.use()](../application#appusepath-callback--callback). A simple example and use case is described below.
+See [app.use()](../application#appusepath-callback--callback) for more information.
 
 Middleware is like a plumbing pipe: requests start at the first middleware function defined
 and work their way "down" the middleware stack processing for each path they match.