Docs: Add a @since note about new parameters with the spread operator added to function signatures.

Props jrf.
See #47678.

git-svn-id: https://develop.svn.wordpress.org/trunk@46451 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-user.php

@@ -730,6 +730,8 @@ class WP_User {
 	 * may produce unreliable results.
 	 *
 	 * @since 2.0.0
+	 * @since 5.3.0 Formalized the existing and already documented `...$args` parameter
+	 *              by adding it to the function signature.
 	 *
 	 * @see map_meta_cap()
 	 *