Clarified warning about date-based generic views.

        When :doc:`time zone support </topics/i18n/timezones>` is enabled and

        ``date_field`` is a ``DateTimeField``, dates are assumed to be in the

        current time zone. As a consequence, if you have implemented per-user

        time zone selection, users living in different time zones may view a

        different set of objects at the same URL.

        current time zone. Otherwise, the queryset could include objects from

        the previous or the next day in the end user's time zone.

        .. warning::

            In this situation, if you have implemented per-user time zone

            selection, the same URL may show a different set of objects,

            depending on the end user's time zone. To avoid this, you should

            use a ``DateField`` as the ``date_field`` attribute.

    .. attribute:: allow_future