Add doc for String and Symbol string_view constructors

Author: cacharle

doc/string.md

@@ -60,6 +60,7 @@ Napi::String::New(napi_env env, const char* value);
 Napi::String::New(napi_env env, const char16_t* value);
 Napi::String::New(napi_env env, const char* value, size_t length);
 Napi::String::New(napi_env env, const char16_t* value, size_t length);
+Napi::String::New(napi_env env, std::string_view value);
 ```
 
 - `[in] env`: The `napi_env` environment in which to construct the `Napi::Value` object.
@@ -68,6 +69,7 @@ Napi::String::New(napi_env env, const char16_t* value, size_t length);
   - `std::u16string&` - represents a UTF16-LE string.
   - `const char*` - represents a UTF8 string.
   - `const char16_t*` - represents a UTF16-LE string.
+  - `std::string_view` - represents a UTF8 string view.
 - `[in] length`: The length of the string (not necessarily null-terminated) in code units.
 
 Returns a new `Napi::String` that represents the passed in C++ string.

doc/symbol.md

@@ -18,6 +18,7 @@ Returns a new empty `Napi::Symbol`.
 ```cpp
 Napi::Symbol::New(napi_env env, const std::string& description);
 Napi::Symbol::New(napi_env env, const char* description);
+Napi::Symbol::New(napi_env env, std::string_view description);
 Napi::Symbol::New(napi_env env, Napi::String description);
 Napi::Symbol::New(napi_env env, napi_value description);
 ```
@@ -27,6 +28,7 @@ Napi::Symbol::New(napi_env env, napi_value description);
   `description` may be any of:
   - `std::string&` - UTF8 string description.
   - `const char*` - represents a UTF8 string description.
+  - `std::string_view` - represents a UTF8 string view.
   - `String` - Node addon API String description.
   - `napi_value` - Node-API `napi_value` description.
 
@@ -58,4 +60,4 @@ static Napi::Symbol Napi::Symbol::For(napi_env env, napi_value description);
 
 Searches in the global registry for existing symbol with the given name. If the symbol already exist it will be returned, otherwise a new symbol will be created in the registry. It's equivalent to Symbol.for() called from JavaScript.
 
-[`Napi::Name`]: ./name.md
+[`Napi::Name`]: ./name.md