Merge branch '2.3' into 2.7

* 2.3:
  unused use instructions
  Fix typo in SwitchUserListener file name
  Changed folder name to lowercase (best practises)

Author: xabbuh

cookbook/event_dispatcher/event_listener.rst

@@ -141,9 +141,7 @@ listen to the same ``kernel.exception`` event::
     namespace AppBundle\EventSubscriber;
 
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
-    use Symfony\Component\HttpFoundation\Response;
     use Symfony\Component\HttpKernel\Event\GetResponseForExceptionEvent;
-    use Symfony\Component\HttpKernel\Exception\HttpExceptionInterface;
 
     class ExceptionSubscriber implements EventSubscriberInterface
     {

cookbook/security/impersonating_user.rst

@@ -224,7 +224,7 @@ how to change the sticky locale:
 
 .. code-block:: php
 
-        // src/AppBundle/EventListener/SwitchUserListener.pnp
+        // src/AppBundle/EventListener/SwitchUserListener.php
         namespace AppBundle\EventListener;
 
         use Symfony\Component\Security\Http\Event\SwitchUserEvent;