Fixed content types contrib app doc typos.

        Clears an internal cache used by

        :class:`~django.contrib.contenttypes.models.ContentType` to keep track

        of which models for which it has created

        of models for which it has created

        :class:`~django.contrib.contenttypes.models.ContentType` instances. You

        probably won't ever need to call this method yourself; Django will call

        it automatically when it's needed.

:meth:`~django.contrib.contenttypes.models.ContentTypeManager.get_for_models`

always returned the :class:`~django.contrib.contenttypes.models.ContentType`

associated with the concrete model of the specified one(s). That means there

was no way to retreive the

was no way to retrieve the

:class:`~django.contrib.contenttypes.models.ContentType` of a proxy model

using those methods. As of Django 1.5 you can now pass a boolean flag –

``for_concrete_model`` and ``for_concrete_models`` respectively – to specify

wether or not you want to retreive the

wether or not you want to retrieve the

:class:`~django.contrib.contenttypes.models.ContentType` for the concrete or

direct model.