Fixed #9033 - Add bullets to QuerySet extra() arguments. thanks julien for the...

Specify one or more of ``params``, ``select``, ``where`` or ``tables``. None

of the arguments is required, but you should use at least one of them.

``select``

    * ``select``

        The ``select`` argument lets you put extra fields in the ``SELECT`` clause.

        It should be a dictionary mapping attribute names to SQL clauses to use to

        calculate that attribute.

        tracking of parameters looks for ``%s`` and an escaped ``%`` character

        like this isn't detected. That will lead to incorrect results.

``where`` / ``tables``

    * ``where`` / ``tables``

        You can define explicit SQL ``WHERE`` clauses -- perhaps to perform

        non-explicit joins -- by using ``where``. You can manually add tables to

        the SQL ``FROM`` clause by using ``tables``.

        construct the queryset in the same way, so you can rely upon the alias

        name to not change.

``order_by``

    * ``order_by``

        If you need to order the resulting queryset using some of the new fields

        or tables you have included via ``extra()`` use the ``order_by`` parameter

        to ``extra()`` and pass in a sequence of strings. These strings should

        ``extra()`` and it will behave as you expect (adding new constraints each

        time).

``params``

    * ``params``

        The ``where`` parameter described above may use standard Python database

        string placeholders -- ``'%s'`` to indicate parameters the database engine

        should automatically quote. The ``params`` argument is a list of any extra