[1.2.X] Fixed #5327 -- Added standardized field information to...

[1.2.X] Fixed #5327 -- Added standardized field information to ModelChoiceField and ModelMultipleChoiceField documentation. Thanks to danielrubio for the report and PhiR for the text.

Backport of [14214] from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@14215 bcc190cf-cafb-0310-a4f2-bffc1f526a37