Update internal ref links

Author: mathieucarbou

docs/concepts.md

@@ -71,4 +71,4 @@
 - Placeholders are delimited with `%` symbols. Like this: `%TEMPLATE_PLACEHOLDER%`.
 - It works by extracting placeholder name from response text and passing it to user provided function which should return actual value to be used instead of placeholder.
 - Since it's user provided function, it is possible for library users to implement conditional processing and cycles themselves.
-- Since it's impossible to know the actual response size after template processing step in advance (and, therefore, to include it in response headers), the response becomes [chunked](#chunked-response).
+- Since it's impossible to know the actual response size after template processing step in advance (and, therefore, to include it in response headers), the response becomes [chunked](responses.md#chunked-response).

docs/setup.md

@@ -139,7 +139,7 @@ void loop(){
 }
 ```
 
-**IMPORTANT**: Authentication should now use `AsyncAuthenticationMiddleware` instead of the deprecated methods. See the [How to use authentication with AsyncAuthenticationMiddleware](middleware.md#how-to-use-authentication-with-asyncauthenticationmiddleware) section.
+**IMPORTANT**: Authentication should now use `AsyncAuthenticationMiddleware` instead of the deprecated methods. See the [Authentication with AsyncAuthenticationMiddleware](middleware.md#authentication-with-asyncauthenticationmiddleware) section.
 
 ### Setup global and class functions as request handlers
 

docs/static-files.md

@@ -123,7 +123,7 @@ handler->setLastModified(date_modified);
 ### Specifying Template Processor callback
 
 It is possible to specify template processor for static files. For information on template processor see
-[Respond with content coming from a File containing templates](#respond-with-content-coming-from-a-file-containing-templates).
+[Respond with content coming from a File containing templates](responses.md#respond-with-content-coming-from-a-file-containing-templates).
 
 ```cpp
 String processor(const String& var)
@@ -206,5 +206,5 @@ webServer.onNotFound([](AsyncWebServerRequest *request) {
 });
 ```
 
-You may want to try [Respond with file content using a callback and extra headers](#respond-with-file-content-using-a-callback-and-extra-headers)
+You may want to try [Respond with file content using a callback and extra headers](responses.md#respond-with-file-content-using-a-callback-and-extra-headers)
 For actual serving the file.