Hygiene: Correct return value type on mw.popups.wait

Change-Id: I0c5c5c1291f413241e855471b71b0e88f6de01c7

resources/ext.popups/wait.js

@@ -11,7 +11,7 @@
 	 * mw.popups.wait( 150 ).then( continueProcessing );
 	 *
 	 * @param {Number} delay The number of milliseconds to wait
-	 * @return {jQuery.Deferred}
+	 * @return {jQuery.Promise}
 	 */
 	mw.popups.wait = function ( delay ) {
 		var result = $.Deferred();