Singular or plural for the module name

[Martin Fischer]

The Specification section of PEP 661 currently says:

A new Sentinel class will be added to a new sentinels module.

Note "sentinels" in plural but goes on with a code example showing sentinel in singular:

 >>> from sentinel import Sentinel

While the latter appears to be a typo, I think singular would actually be preferable to plural to be consistent with the enum module, which is called enum instead of enums, so I think the sentinel module should also be called sentinel instead of sentinels.