PEP 518: Do not mention wheel in default [build-system] requires

[hroncok]

It was never necessary. In the past, setuptools would pull it in through the PEP 517 hook, only when building the wheels. During PyCon 2024, though, wheel moved into the setuptools' codebase and so it's always bundled now, in the modern versions.

• Change is either:
  • To a Draft PEP
  • To an Accepted or Final PEP, with Steering Council approval
  • To fix an editorial issue (markup, typo, link, header, etc)
• PR title prefixed with PEP number (e.g. PEP 123: Summary of changes)

cc @webknjaz, whose rationale I copied to the commit message.

This is a change to an accepted/final PEP and is not editorial, but reflects the reality. Is Steering Council approval necessary?

(Edited by @ncoghlan: I think this is an editorial change, since it's just fixing a bug in the example config rather than changing anything in the specification. I have merged it on that basis)

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📚 Documentation preview 📚: https://pep-previews--4603.org.readthedocs.build/

[hugovk]

Normally we don't update historical PEPs and prefer to update the living spec instead, but we don't have the canonical-pypa-spec header on this one (it'd be good to add it?).

And it might be worth updating this as well -- I'll leave that decision to the PEP authors. I don't think we need SC approval.

[webknjaz]

I think it's good to update since I've been observing people copying this into new projects but never knew where they kept finding the bad example.. The PyPUG link might be good to have but I don't think that should block this PR.

[webknjaz]

cc @ncoghlan

[ncoghlan]

I think the history here is that we wrote the PEP 518 examples before setuptools wrote their PEP 517 hook implementation, so it wasn't a given that the extra dependency declaration would be redundant.

If anyone wants to add a canonical reference header, the relevant target would be https://packaging.python.org/en/latest/specifications/pyproject-toml/#declaring-build-system-dependencies-the-build-system-table (I won't hold this PR up for that, though)

[ncoghlan]

For checklist completion, I marked it as an editorial change (as the commit message states, this explicit dependency declaration was never necessary in practice, we just didn't know it wasn't going to be necessary when the PEP was written)