fixed RST syntax

fabpot · fabpot · commit f47a48a3d49a · 2018-03-01T14:27:17.000-08:00
diff --git a/configuration/external_parameters.rst b/configuration/external_parameters.rst
@@ -124,7 +124,7 @@ You can now reference these parameters wherever you need them.
 
         </container>
 
-    ::
+    .. code-block:: php
 
         $container->loadFromExtension('doctrine', array(
             'dbal' => array(
