Minor reword

Author: javiereguiluz

security.rst

@@ -911,7 +911,8 @@ Users with the ``ROLE_ADMIN`` role will also have the
 ``ROLE_USER`` role. And users with ``ROLE_SUPER_ADMIN``, will automatically have
 ``ROLE_ADMIN``, ``ROLE_ALLOWED_TO_SWITCH`` and ``ROLE_USER`` (inherited from ``ROLE_ADMIN``).
 
-For role hierarchy to work, do not try to call ``$user->getRoles()`` manually in a controller::
+For role hierarchy to work, do not try to call ``$user->getRoles()`` manually.
+For example, in a controller extending from the :ref:`base controller <the-base-controller-class-services>`::
 
     // BAD - $user->getRoles() will not know about the role hierarchy
     $hasAccess = in_array('ROLE_ADMIN', $user->getRoles());