minor #5072 Add missing use statement in Building Login Form doc (ock…

…cyp)

This PR was merged into the 2.3 branch.

Discussion
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Add missing use statement in Building Login Form doc

Also removed use statement for Route as it is only needed
when using annotations for routing

 Q                 | A
 -------------    | ---
 Doc fix?       | yes
 New docs?  | no
 Applies to    | all
 Fixed tickets | #5072

Commits
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712a858 Add missing use statement in Building Login Form doc Also removed use statement for Route as it is only needed when using annotations for routing

cookbook/security/form_login_setup.rst

@@ -82,6 +82,7 @@ bundle::
     namespace AppBundle\Controller;
 
     use Symfony\Bundle\FrameworkBundle\Controller\Controller;
+    use Symfony\Component\HttpFoundation\Request;
 
     class SecurityController extends Controller
     {