Merge branch '3.4' into 4.0

* 3.4:
  fixed RST syntax

Author: fabpot

configuration/external_parameters.rst

@@ -61,7 +61,7 @@ This variable is referenced in the service container configuration using
 
         </container>
 
-    ::
+    .. code-block:: php
 
         // config/packages/doctrine.php
         $container->loadFromExtension('doctrine', array(