Update Application Passwords (#149)

Updating the documentation to reflect that Application Passwords is now part of WordPress Core as of 5.6 and adding information on how to use it to authenticate with the REST API. https://make.wordpress.org/core/2020/11/05/application-passwords-integration-guide/

Author: cagrimmett

using-the-rest-api/authentication.md

@@ -55,14 +55,26 @@ $.ajax( {
 
 Note that you do not need to verify that the nonce is valid inside your custom end point. This is automatically done for you in `rest_cookie_check_errors()`.
 
+## Basic Authentication with Application Passwords
+
+As of 5.6, WordPress has shipped with [Application Passwords](https://make.wordpress.org/core/2020/11/05/application-passwords-integration-guide/), which can be generated from an Edit User page (wp-admin -> Users -> Edit User). 
+
+The credentials can be passed along to REST API requests served over https:// using [Basic Auth](https://ec.haxx.se/http/http-auth) / [RFC 7617](https://tools.ietf.org/html/rfc7617) — [here’s the documentation for how to use it with cURL](https://ec.haxx.se/http/http-auth).
+
+For a simple command-line script example, just swap out USERNAME, PASSWORD, and HOSTNAME in this with their respective values:
+
+```
+curl --user "USERNAME:PASSWORD" https://HOSTNAME/wp-json/wp/v2/users?context=edit
+```
+
 ## Authentication Plugins
 
-While cookie authentication is the only authentication mechanism available natively within WordPress, plugins may be added to support alternative modes of authentication that will work from remote applications. Some example plugins are [OAuth 1.0a Server](https://wordpress.org/plugins/rest-api-oauth1/), [Application Passwords](https://wordpress.org/plugins/application-passwords/), and [JSON Web Tokens](https://wordpress.org/plugins/jwt-authentication-for-wp-rest-api/).
+Plugins may be added to support alternative modes of authentication that will work from remote applications. Some example plugins are [OAuth 1.0a Server](https://wordpress.org/plugins/rest-api-oauth1/) and [JSON Web Tokens](https://wordpress.org/plugins/jwt-authentication-for-wp-rest-api/).
 
 [info]
 
 There's also a [Basic Authentication](https://github.com/WP-API/Basic-Auth) plugin.
 
-Note that this plugin requires sending your username and password with every request, and should only be used for development and testing i.e. not in a production environment.
+Note that this plugin requires sending your username and password with every request, and should only be used for development and testing i.e. not in a production environment. Using Application Passwords (see above) is preferred.
 
 [/info]