Fix ast deprecation warnings up to Python 3.13.

[fschulze]

Wasn't so trivial after all ...

The changes have less specific types than before, as all of ast.Num, ast.Str and ast.Index become ast.Constant. This has been the case since Python 3.9 and it worked fine. I added additional isinstance checks. Not sure those are required or even harmful for some usecases.

Node.lineno can't be None, but also can't be omitted. I added ast.copy_location and ast.fix_missing_locations calls, but I'm not sure they do the desired thing at each place, as I don't fully understand what the places they are used are actually doing.

For the visit_FunctionDef transformer I couldn't find a more elegant solution to fix mypy. The type_params doesn't seem to be required, as the tests work without, but the type definition (and docs) seems to say otherwise.

[coveralls]

Pull Request Test Coverage Report for Build 12408949077

Details

• 41 of 42 (97.62%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.01%) to 92.34%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/chameleon/codegen.py	19	20	95.0%

Totals
Change from base Build 12408666775:	-0.01%
Covered Lines:	3921
Relevant Lines:	4172

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💛 - Coveralls

[malthe]

@fschulze I don't understand the point about having to fix-up location, see https://github.com/malthe/chameleon/actions/runs/12455642989 – testing this commit: 9155eb4.

This seems to run just fine across the different versions.

[fschulze]

It failed with AttributeError for the other cases where I added it. I don't understand it either, as I already wrote in the description of this PR.