gh-108901: Deprecate inspect.getfullargspec and slate it for removal in 3.15

[sobolevn]

I've create a new PyPI package to backport skip_bound_arg parameter to previous versions: https://github.com/wemake-services/inspect313

It is not yet published, please let me know if I need to add someone as maintainer / move it somewhere.

• Issue: Add modern alternatives to inspect module, deprecate old incorrect APIs #108901

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📚 Documentation preview 📚: https://cpython-previews--112314.org.readthedocs.build/

[hugovk]

Would probably also be a good idea to update the advice in https://docs.python.org/3/whatsnew/3.11.html?highlight=getfullargspec#removed so it no longer recommends getfullargspec:

The getargspec() function, deprecated since Python 3.0; use inspect.signature() or inspect.getfullargspec() instead.

[sobolevn]

@hugovk Thanks! This would need a separate PR.

[encukou]

What's the reason to use the minimum length of the deprecation period?

[sobolevn]

No real reason, I think that the transition will be rather smooth, considering the existance of https://github.com/wemake-services/inspect313

But, we can set any remove= version, this is not really a problem :)