Add type hints to wcwidth for better IDE support

[su2u4-1]

Written by chatGPT

Background
Currently, the wcwidth library does not include any type hints, which prevents IDEs and static type checkers (e.g., mypy, Pyright) from inferring parameter and return types correctly.

Proposal

• Add .pyi stub files or inline type annotations following PEP 484 to provide comprehensive type information.
• Optionally, contribute the stubs to typeshed or publish a separate types-wcwidth package on PyPI.

Benefits

• Improved IDE auto-completion and documentation lookup.
• Enhanced compatibility with static type checkers, reducing potential runtime errors.
• Easier onboarding for new contributors and users who rely on type safety.

---

I’m not a native English speaker and used a translation tool—please feel free to suggest any wording improvements!

I wrote it myself

wcwidth does not contain any type hint, so the IDE cannot correctly infer the type
Therefore, I suggest adding type hint, such as adding .pyi file

Because my English is not good, I used Google Translate and chatGPT, please forgive me.

[GalaxySnail]

Previously discussed in #71.

By the way, there is currently a stub-only package for wcwidth on PyPI: wcwidth-stubs (#102 (comment)). If you need type information for wcwidth, you can use it for now.

[su2u4-1]

Thank you very much, I'm sorry I didn't check if there is any related issue first