Docs: Document the usage of `$current_user` global in `get_user_by()`.

Follow-up to [50790].

Props paaggeli, mukesh27.
Fixes #53088.
Built from https://develop.svn.wordpress.org/trunk@50792


git-svn-id: http://core.svn.wordpress.org/trunk@50401 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/pluggable.php

@@ -93,6 +93,8 @@ if ( ! function_exists( 'get_user_by' ) ) :
 	 * @since 4.4.0 Added 'ID' as an alias of 'id' for the `$field` parameter.
 	 * @since 5.8.0 Returns the global `$current_user` if it's the user being fetched.
 	 *
+	 * @global WP_User $current_user The current user object which holds the user data.
+	 *
 	 * @param string     $field The field to retrieve the user with. id | ID | slug | email | login.
 	 * @param int|string $value A value for $field. A user ID, slug, email address, or login name.
 	 * @return WP_User|false WP_User object on success, false on failure.

wp-includes/version.php

@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50791';
+$wp_version = '5.8-alpha-50792';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.