minor #12500 Replace GetResponseEvent with RequestEvent (apiv-thomas)

This PR was submitted for the master branch but it was merged into the 4.3 branch instead (closes #12500).

Discussion
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Replace GetResponseEvent with RequestEvent

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Commits
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72f8b5a Replace GetResponseEvent with RequestEvent

Author: javiereguiluz

security/form_login_setup.rst

@@ -435,7 +435,7 @@ whenever the user browses a page::
 
     use Symfony\Component\EventDispatcher\EventSubscriberInterface;
     use Symfony\Component\HttpFoundation\Session\SessionInterface;
-    use Symfony\Component\HttpKernel\Event\GetResponseEvent;
+    use Symfony\Component\HttpKernel\Event\RequestEvent;
     use Symfony\Component\HttpKernel\KernelEvents;
     use Symfony\Component\Security\Http\Util\TargetPathTrait;
 
@@ -450,7 +450,7 @@ whenever the user browses a page::
             $this->session = $session;
         }
 
-        public function onKernelRequest(GetResponseEvent $event): void
+        public function onKernelRequest(RequestEvent $event): void
         {
             $request = $event->getRequest();
             if (!$event->isMasterRequest() || $request->isXmlHttpRequest()) {