Run mypy on `Tools/wasm`

[sobolevn]

Feature or enhancement

Right now we already have 3 fully typed and checked tools:

• Add type annotations to clinic.py #104050
• Run mypy on Tools/peg_generator #108455
• Run mypy on cases_generator #104504

I think we can also add Tools/wasm quite easily to this list.
Tools/wasm already has most of the type annotations, but there are some mypy errors to fix.

Linked PRs

• gh-109125: Run mypy on Tools/wasm #109126
• [3.12] gh-109125: Run mypy on Tools/wasm (GH-109126) #109561

[brettcannon]

I'm not sure if it's worth keeping a couple of scripts typed, especially based on the restrictions of typing in the repo (e.g., older versions of Python w/o typing_extensions access, etc.). I honestly would be fine stripping out the types in the scripts in that directory rather than try to keep the types working.

[corona10]

We may need to define the scope of what scripts would be worth adding typing, and applying mypy pipeline.

cc @AlexWaygood @erlend-aasland @vstinner

[AlexWaygood]

We may need to define the scope of what scripts would be worth adding typing, and applying mypy pipeline.

I'm not sure this needs to be formalised much. I think we should add mypy to CI for self-contained CPython projects where the maintainers of those projects say they'd find it useful. We should avoid doing so for projects where the maintainers of those projects say it wouldn't be useful.

[vstinner]

Once I will be done with refactoring libregrtest #109162 I will need help to add type hints there ;-) IMO it would be a more interesting target than Tools/wasm/ scripts.

[hugovk]

Done via #109126, thanks!