Add missing return types to controllers

lib/Controller/PageController.php

@@ -44,10 +44,14 @@ class PageController extends Controller {
 	 *          basically the only required method to add this exemption, don't
 	 *          add it to any other method if you don't exactly know what it does
 	 *
+	 *
 	 * @NoAdminRequired
+	 *
 	 * @NoCSRFRequired
+	 *
+	 * @return TemplateResponse
 	 */
-	public function index() {
+	public function index(): TemplateResponse {
 		return new TemplateResponse($this->appName, 'main');
 	}