[ticket/13713] Use is-active class instead of cur for current items

PHPBB3-13713

phpBB/assets/javascript/editor.js

@@ -616,7 +616,7 @@ function getCaretPosition(txtarea) {
 				trigger: '@',
 				allowSpaces: true,
 				containerClass: 'mention-container',
-				selectClass: 'cur',
+				selectClass: 'is-active',
 				itemClass: 'mention-item',
 				menuItemTemplate: function (data) {
 					const itemData = data;