Doc'd Jinja2 form renderer.

docs/ref/settings.txt

@@ -1672,7 +1672,10 @@ generate correct URLs when ``SCRIPT_NAME`` is not ``/``.
 Default: ``'``:class:`django.forms.renderers.DjangoTemplates`\ ``'``
 
 The class that renders form widgets. It must implement :ref:`the low-level
-render API <low-level-widget-render-api>`.
+render API <low-level-widget-render-api>`. Included form renderers are:
+
+* ``'``:class:`django.forms.renderers.DjangoTemplates`\ ``'``
+* ``'``:class:`django.forms.renderers.Jinja2`\ ``'``
 
 .. setting:: FORMAT_MODULE_PATH