render() is a Twig function, not a block

Correct a typo which cause a Twig exception because the _render_ block is called but it doesn't exist.

Author: damienflament

bundles/create/introduction.rst

@@ -368,7 +368,7 @@ higher, the method reads:
 
     .. code-block:: jinja
 
-        {% render(controller("cmf_create.jsloader.controller:includeJSFilesAction")) %}
+        {{ render(controller("cmf_create.jsloader.controller:includeJSFilesAction")) }}
 
     .. code-block:: php