Fixed #8662 -- Fixed the documentation of Model.save() to match the real

To save an object back to the database, call ``save()``:

.. method:: Model.save([raw=False])

.. method:: Model.save([force_insert=False, force_update=False])

Of course, there's some subtleties; see the sections below.

**New in Django development version:** The signature of the ``save()`` method

has changed from earlier versions (``force_insert`` and ``force_update`` have

been added). If you are overriding these methods, be sure to use the correct

signature.

Auto-incrementing primary keys

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