Add closure variables into global scope

[kai3341]

Fixes #430

[adamchainz]

I think you're off to a good start, but this is failing the tests. Please try running the tests locally with e.g. tox -e py311. Also, add some tests covering class closures, and a chaneglog note.

[kai3341]

I reproduced test fails and fixed it
Also I added new test with my code example. The most funny that these changes are work in my project but the test is failing with initial error which I try to solve
I'll continue working on this issue

[kai3341]

Type of cell_contents is Any. So I'm NOT SURE here
Is it better to check if cell_contents is type instance?
What else may it be?

[kai3341]

So, I was right in this question

[adamchainz]

Also I added new test with my code example.

I don't see this test? Or a changelog note.

[adamchainz]

I just added two tests which fail. func.__closure__ is None in the both cases. I'm not sure why it's not there...