REST API: Include enum and description in help data.

Props lcherpit.
Fixes #34543.

Built from https://develop.svn.wordpress.org/trunk@35652


git-svn-id: http://core.svn.wordpress.org/trunk@35616 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/rest-api/class-wp-rest-server.php

@@ -1064,6 +1064,12 @@ class WP_REST_Server {
 					if ( isset( $opts['default'] ) ) {
 						$arg_data['default'] = $opts['default'];
 					}
+					if ( isset( $opts['enum'] ) ) {
+						$arg_data['enum'] = $opts['enum'];
+					}
+					if ( isset( $opts['description'] ) ) {
+						$arg_data['description'] = $opts['description'];
+					}
 					$endpoint_data['args'][ $key ] = $arg_data;
 				}
 			}