[1.1.X] Fixed #11973 -- Corrected some misleading documentation regarding the...

[1.1.X] Fixed #11973 -- Corrected some misleading documentation regarding the feed_copyright attribute on feeds.

Backport of a small part of r12338 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12339 bcc190cf-cafb-0310-a4f2-bffc1f526a37