update versionadded directive to match the content

Author: xabbuh

cookbook/security/voters.rst

@@ -207,9 +207,10 @@ How to Use the Voter in a Controller
 ------------------------------------
 
 The registered voter will then always be asked as soon as the method ``isGranted()``
-from the authorization checker is called.
-
-.. code-block:: php
+from the authorization checker is called. When extending the base ``Controller``
+class, you can simply call the
+:method:`Symfony\\Bundle\\FrameworkBundle\\Controller\\Controller::denyAccessUnlessGranted()`
+method::
 
     // src/AppBundle/Controller/PostController.php
     namespace AppBundle\Controller;
@@ -232,9 +233,9 @@ from the authorization checker is called.
     }
 
 .. versionadded:: 2.6
-    The ``security.authorization_checker`` service was introduced in Symfony 2.6.
-    Prior to Symfony 2.6, you had to use the ``isGranted()`` method of the
-    ``security.context`` service.
+    The ``denyAccessUnlessGranted()`` method was introduced in Symfony 2.6.
+    Prior to Symfony 2.6, you had to call the ``isGranted()`` method of the
+    ``security.context`` service and throw the exception yourself.
 
 It's that easy!