Add missing use case for Response

Author: thrashzone13

routing.rst

@@ -70,6 +70,7 @@ do so, create a :doc:`controller class </controller>` like the following:
         namespace App\Controller;
 
         use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+        use Symfony\Component\HttpFoundation\Response;
         use Symfony\Component\Routing\Annotation\Route;
 
         class BlogController extends AbstractController