Fill out inline documentation for the `__call()` magic method added to the `WP_Roles` class in [28503].

See #22234 and #28885.

Built from https://develop.svn.wordpress.org/trunk@29153


git-svn-id: http://core.svn.wordpress.org/trunk@28937 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/capabilities.php

@@ -82,12 +82,14 @@ class WP_Roles {
 	}
 
 	/**
-	 * Make private/protected methods readable for backwards compatibility
+	 * Make private/protected methods readable for backwards compatibility.
 	 *
 	 * @since 4.0.0
-	 * @param string $name
-	 * @param array $arguments
-	 * @return mixed
+	 * @access public
+	 *
+	 * @param callable $name      Method to call.
+	 * @param array    $arguments Arguments to pass when calling.
+	 * @return mixed|bool Return value of the callback, false otherwise.
 	 */
 	public function __call( $name, $arguments ) {
 		return call_user_func_array( array( $this, $name ), $arguments );