Merge branch '6.4' into 7.1

* 6.4:
  [Security] Fix the namespace of a code example
  Update mercure.rst: Deleting forgotten(?) sentence

Author: javiereguiluz

mercure.rst

@@ -684,8 +684,6 @@ Debugging
 
     The WebProfiler panel was introduced in MercureBundle 0.2.
 
-Enable the panel in your configuration, as follows:
-
 MercureBundle is shipped with a debug panel. Install the Debug pack to
 enable it::
 

security.rst

@@ -1744,7 +1744,7 @@ You can log in a user programmatically using the ``login()`` method of the
 :class:`Symfony\\Bundle\\SecurityBundle\\Security` helper::
 
     // src/Controller/SecurityController.php
-    namespace App\Controller\SecurityController;
+    namespace App\Controller;
 
     use App\Security\Authenticator\ExampleAuthenticator;
     use Symfony\Bundle\SecurityBundle\Security;