Resolve #2774071: Fix Drupal.Scope.MethodScope.Missing, Drupal.NamingConventions.ValidFunctionName.NotCamelCaps

Issue #2774071 Fix Visibility must be declared on method (Drupal.Scope.MethodScope.Missing)

src/Controller/TokenTreeController.php

@@ -34,7 +34,7 @@ class TokenTreeController extends ControllerBase {
   /**
    * Page callback to output a token tree as an empty page.
    */
-  function outputTree(Request $request) {
+  public function outputTree(Request $request) {
     $options = $request->query->has('options') ? Json::decode($request->query->get('options')) : [];
 
     // The option token_types may only be an array OR 'all'. If it is not set,