Fixed typo in internal CharField method
Fixed spelling in model_forms test class names
Fixed #22085 -- Added a feature for setting non-expiring keys as the default.

This feature allows the default `TIMEOUT` Cache argument to be set to `None`,
so that cache instances can set a non-expiring key as the default,
instead of using the default value of 5 minutes.

Previously, this was possible only by passing `None` as an argument to
the set() method of objects of type `BaseCache` (and subtypes).
Added tests for MTI in RunPython.
Fixed #21893 -- ModelState didn't account for MTI parents inherited from abstract models.
Merge pull request #2396 from loic/ticket21893

Fixed #21893 -- ModelState didn't account for MTI parents inherited from abstract models.
Fixed incorrect docstring in cache tests