minor symfony#13694 Update security.rst (amine-betari)

This PR was merged into the 4.4 branch.

Discussion
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Update security.rst

- Fix name of  route (app_logout instead of logout in PHP configuration)

Commits
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e33d34a Update security.rst

Author: javiereguiluz

security.rst

@@ -881,7 +881,7 @@ Next, you'll need to create a route for this URL (but not a controller):
         use Symfony\Component\Routing\Loader\Configurator\RoutingConfigurator;
 
         return function (RoutingConfigurator $routes) {
-            $routes->add('logout', '/logout')
+            $routes->add('app_logout', '/logout')
                 ->methods(['GET'])
             ;
         };