Docs: Remove ambiguity.

The docs to the LANGUAGES setting were using both the term language code
and language name for the same thing.
Merge pull request #956 from maikhoepfel/master

Removed ambiguity regarding LANGUAGES setting
Improved FormView docs in class-based views index.

Thanks Stefan Berder.
Fix #20158: invalid code in queryset_pickle test models.
Merge pull request #975 from bmispelon/ticket-20158

Fix #20158: invalid code in queryset_pickle test models.
Fixed #14540 -- Added Porto-Rico specific formats

Thanks rosarior for the report and the file proposal.
Fixed #20159 -- Mispelled attribute in multi-db documentation example.

Thanks to sane4ka.sh at gmail for the report!
Fixed #20160 -- Erronous reference to `module_name` in admin doc.

Ref #19689.
Fixed #20150 -- Fixed an error in manager doc example
Fixed setup.py overlaid-install warning.

Before this change, if you had a global Django installation in /usr/local/, you
might get a spurious warning when installing Django within a virtualenv.

Thanks epicserve for the report and debugging help.
Merge pull request #977 from nims11/ticket_20150

Fixed #20150 -- Fixed an error in manager doc example
Fixed #15379 - Added "how to cite Django" to FAQ.

Thanks Russ and Susan Tan.