Fixed #22647 -- Documented redirect_field_name keyword argument for user_passes_test.

            return HttpResponse("You can't vote in this poll.")

        # ...

.. function:: user_passes_test(func, [login_url=None])

.. function:: user_passes_test(func, [login_url=None, redirect_field_name=REDIRECT_FIELD_NAME])

    As a shortcut, you can use the convenient ``user_passes_test`` decorator::

    automatically check that the :class:`~django.contrib.auth.models.User` is

    not anonymous.

    :func:`~django.contrib.auth.decorators.user_passes_test()` takes an

    optional ``login_url`` argument, which lets you specify the URL for your

    login page (:setting:`settings.LOGIN_URL <LOGIN_URL>` by default).

    :func:`~django.contrib.auth.decorators.user_passes_test` takes two

    optional arguments:

    ``login_url``

       Lets you specify the URL that users who don't pass the test will be

       redirected to. It may be a login page and defaults to

       :setting:`settings.LOGIN_URL <LOGIN_URL>` if you don't specify one.

    ``redirect_field_name``

       Same as for :func:`~django.contrib.auth.decorators.login_required`.

       Setting it to ``None`` removes it from the URL, which you may want to do

       if you are redirecting users that don't pass the test to a non-login

       page where there's no "next page".

    For example::