DOC: tp_watch was added to PyTypeObject but is not documented

[mattip]

Documentation

PR #97875 extended the PyTypeObject structure with a new tp_watch field. It should be documented in the tp slots section, the PyTypeObject struct definition, and the PyTypeObject slots sections of typeobject.rst

Linked PRs

• gh-99767: update PyTypeObject docs for type watchers #99928
• gh-99767: mark PyTypeObject.tp_watched as internal use only in table #100271

[mattip]

xref @carljm as the author of #97875

[carljm]

Thanks! I'll work on a PR with these doc updates.

[mattip]

Thanks. Documenting it makes it easier for things like cython to know what to do.