[1.7.x] Fixed docs/ref/contrib/auth.txt so that sphinx links work properly.

:class:`~django.contrib.auth.models.Permission` objects have the following

fields:

.. class:: models.Permission

    .. attribute:: name

        Required. 50 characters or fewer. Example: ``'Can vote'``.

    .. attribute:: content_type

    Required. A reference to the ``django_content_type`` database table, which

    contains a record for each installed Django model.

        Required. A reference to the ``django_content_type`` database table,

        which contains a record for each installed model.

    .. attribute:: codename

:class:`~django.contrib.auth.models.Group` objects have the following fields:

.. class:: models.Group

    .. attribute:: name

        Required. 80 characters or fewer. Any characters are permitted. Example: