feat: new hook `action:topics.loading` (in the same format as `action:posts.loading`)

public/src/modules/topicList.js

@@ -250,6 +250,8 @@ define('topicList', [
 		};
 		tplData.template[templateName] = true;
 
+		$(window).trigger('action:topics.loading', { topics: topics, after: after, before: before });
+
 		app.parseAndTranslate(templateName, 'topics', tplData, function (html) {
 			topicListEl.removeClass('hidden');
 			$('#category-no-topics').remove();