Added some further clarification to the docs for Meta.managed.
Added some further clarification to the docs for Meta.managed.

Not sure if any of these are noticed as omissions yet; it's too new.
Primarily trying to head off questions in the future.

--HG--
extra : convert_revision : svn%3Abcc190cf-cafb-0310-a4f2-bffc1f526a37/django/trunk%4010107

adieu/django-nonrel,adieu/django-nonrel,adieu/django-nonrel