Add a versionchanged note that returning cleaned_data is no longer required in clean()

[anonymous]

The two examples of a form clean method at the very bottom of ​https://docs.djangoproject.com/en/dev/ref/forms/validation/ should make it clear that the cleaned_data dict needs to be returned at the end of the method. This can be fixed by simply adding the line "return cleaned_data" at the end of each function.

[Tim Graham]

This has changed in the development version of Django (see [fb1dd6b13a] and [1c4a9bd9ad1]) so that returning cleaned_data is no longer required, however, it would be good to add a versionchanged note about that in this section.

[Daniele Procida]

I would like to reserve this ticket for first-time committers who take
part in the [​http://www.djangocon.us/schedule/presentation/7/ Don't be
afraid to commit tutorial] and the sprints at [​http://djangocon.us/
DjangoCon US 2013] in September.

However, if you want to tackle this ticket before then, please don't
hesitate. Feel free to re-assign it to yourself and do whatever you like
to it.

[Tim Graham <timograham@…>]

In ebfe42d018b1268969238a5b90bfb5fe46d0d44f:

Fixed #21009 -- Added a versionchanged note regarding changes to clean().

refs [fb1dd6b13a] and [1c4a9bd9ad1]