[FR] Warn when invalid table [tools.setuptools] is present in pyproject.toml

[SnoopJ]

What's the problem this feature will solve?

It is pretty easy to incorrectly spell the name of the table where setuptools metadata is declared, i.e. writing:

[tools.setuptools]

instead of:

[tool.setuptools]

And when setuptools metadata is not recognized because of this, it can be a slightly mysterious failure, even for experts, because the errant section is silently ignored.

Describe the solution you'd like

It would be nice if setuptools issued a warning when the invalid [tools.setuptools] table is present in a project's metadata, to provide a hint for users that their metadata has a typo.

Alternative Solutions

No response

Additional context

This has cropped up in #3803, and #3683 also includes an incidental example of this spelling error. I can also say that I have made this mistake multiple times. It feels like the kind of issue you only know to avoid when you've stubbed your toe on it a few times.

Code of Conduct

• I agree to follow the PSF Code of Conduct