minor symfony#11249 use :: instead of .. code-block:: php (OskarStark)

This PR was merged into the 3.4 branch.

Discussion
----------

use :: instead of .. code-block:: php

Commits
-------

6b107ba use :: instead of .. code-block:: php

Author: OskarStark

components/config/definition.rst

@@ -403,7 +403,7 @@ has a certain value:
     (``null``, ``true``, ``false``), provide a replacement value in case
     the value is ``*.``
 
-.. code-block:: php
+The following example shows these methods in practice::
 
     $rootNode
         ->children()