Docs: Correct parameter name for rest_menu_read_access filter.

The filter's third parameter was incorrectly named `$this`, which is not a valid parameter name.

Follow-up to [59718], [59734].

Props justlevine.
See #63268.

git-svn-id: https://develop.svn.wordpress.org/trunk@60172 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/rest-api/endpoints/class-wp-rest-menu-items-controller.php

@@ -88,7 +88,7 @@ protected function check_has_read_only_access( $request ) {
 		 * @param bool               $read_only_access Whether the current user has read access to menu items
 		 *                                             via the REST API.
 		 * @param WP_REST_Request    $request          Full details about the request.
-		 * @param WP_REST_Controller $this             The current instance of the controller.
+		 * @param WP_REST_Controller $controller       The current instance of the controller.
 		 */
 		$read_only_access = apply_filters( 'rest_menu_read_access', false, $request, $this );
 		if ( $read_only_access ) {