Fixed incorrect docstring in cache tests (take two)

3e25c8ac69ae336102d91f1d2591ab03f3a91e33 was an incomplete
merge of the pull request.

Thanks to @ramast for catching this.
Really hidden warnings in javascript_quote tests

Refs #21725.
Fixed #22206 -- Passed models.TextField.max_length to forms.CharField.maxlength
Fixed #14549 - Removed restriction of single FKs on intermediary tables

Thanks to Loic Bistuer for review. Minor changes to error messages
done by committer.
Fixed #22207 -- Added support for GenericRelation reverse lookups

GenericRelation now supports an optional related_query_name argument.
Setting related_query_name adds a relation from the related object back to
the content type for filtering, ordering and other query operations.

Thanks to Loic Bistuer for spotting a couple of important issues in
his review.
Fixed issues and added new scripts to urlify.js

Added the following scripts:
* Lithuanian (thanks to petraszd for the patch)
* Serbian (thanks to offy)
* Azerbajani (thanks to Ali Ismayilov)

Fixed the following issues:
* In Polish character map, some uppercase letters were
  converted to a lowercase ascii equivalent.
* The letter Y with a diaeresis had a lowercase version but no uppercase.

The code was also simplified and cleaned up:
* Use of `var` statements everywhere
* Systematic use of semicolons
* Proper looping over arrays and objects.

Thanks to @oinopion for his help in getting the javascript
into proper shape.

Fixes #8561, #11035.