Fixed #13524 -- Added backwards compatibility and feature notes regarding...

Fixed #13524 -- Added backwards compatibility and feature notes regarding admin inlines and formsets. Thanks to Ramiro Morales and Gabriel Hurley.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13241 bcc190cf-cafb-0310-a4f2-bffc1f526a37