Removed some ReST links to undocumented functions.

  For example, if you use multi-inheritance, you need to define custom primary

  key fields on parent models, otherwise the default ``id`` fields will clash.

* :meth:`~django.utils.translation.parse_accept_lang_header` now returns

* ``django.utils.translation.parse_accept_lang_header()`` now returns

  lowercase locales, instead of the case as it was provided. As locales should

  be treated case-insensitive this allows us to speed up locale detection.

* :meth:`~django.utils.translation.get_language_from_path` and

  :meth:`~django.utils.translation.trans_real.get_supported_language_variant`

* ``django.utils.translation.get_language_from_path()`` and

  ``django.utils.translation.trans_real.get_supported_language_variant()``

  now no longer have a ``supported`` argument.

.. _deprecated-features-1.7: