Document use of Manager rather than BaseManager for from_queryset()

[Jonatas CD]

Following #26953, document the use of Manager rather that BaseManager on 1.9+ to avoid crash with AssertionError.

Currently the example [1] uses BaseManager while in the preceding paragraph is Manager.
[1] ​https://docs.djangoproject.com/en/dev/topics/db/managers/#from-queryset

[Tim Graham]

A BaseManager is defined in that example that's different from django.db.models.manager.BaseManager. Does the example not work as written?

[Jonatas CD]

My idea was to keep the example to text - specially after that mentioned ticket.

[Tim Graham]

I'm not sure what you mean by "keep the example to text". django.db.models.manager.BaseManager isn't a documented API, so I don't see the reason why we'd need a note saying not to use something that's not documented. Anyway, will you propose a patch?

[Jonatas CD]

sure. I'll do it

[Carlton Gibson]

​PR

[GitHub <noreply@…>]

In a2f55424:

Fixed #27865 -- Adjusted docs example to avoid confusion with models.BaseManager.

[Carlton Gibson <carlton.gibson@…>]

In 0f524f56:

[3.0.x] Fixed #27865 -- Adjusted docs example to avoid confusion with models.BaseManager.

Backport of a2f554249ec07d4643643773a995579f98564ac1 from master