[1.6.x] Fixed #21396: Document backwards-incompatible change in RedirectView.get_redirect_url.

    **Methods**

    .. method:: get_redirect_url(**kwargs)

    .. method:: get_redirect_url(*args, **kwargs)

        Constructs the target URL for redirection.

        .. versionchanged:: 1.6

            The signature of this method was changed to include ``*args``.

        The default implementation uses :attr:`url` as a starting

        string, performs expansion of ``%`` parameters in that string, as well

        as the appending of query string if requested by :attr:`query_string`.

        string and performs expansion of ``%`` named parameters in that string

        using the named groups captured in the URL.

        If :attr:`url` is not set, ``get_redirect_url()`` tries to reverse the

        :attr:`pattern_name` using what was captured in the URL (both named and

        unnamed groups are used).

        If requested by :attr:`query_string`, it will also append the query

        string to the generated URL.

        Subclasses may implement any behavior they wish, as long as the method

        returns a redirect-ready URL string.

  been removed. Use ``socket.error`` provided by the standard library instead.

  This change was also released in Django 1.5.5.

* The signature of :meth:`django.views.generic.base.RedirectView.get_redirect_url`

  has changed and now accepts positional arguments as well (``*args, **kwargs``).

  Any unnamed captured group will now be passed to ``get_redirect_url()``

  which may result in a ``TypeError`` if you don't update the signature of your

  custom method.

Features deprecated in 1.6

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