Fixed #13188 -- Moved date format documentation from the now template tag to...

Fixed #13188 -- Moved date format documentation from the now template tag to the date filter. Thanks, dwillis and timo.

Backport from trunk (r14013).

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14021 bcc190cf-cafb-0310-a4f2-bffc1f526a37