[1.1.X] Fixed `fieldlookup` docs cross-reference directive, and added it to...

[1.1.X] Fixed `fieldlookup` docs cross-reference directive, and added it to the queryset reference.  Refs #12930.

Backport of r12808 from trunk.


git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.1.X@12809 bcc190cf-cafb-0310-a4f2-bffc1f526a37