Suggest how stub packages can be tied to the appropriate version of their parent package

[brettcannon]

Over at https://discuss.python.org/t/allow-package-references-as-version-specifiers/19226/ someone asked for a packaging feature to help keep type stub packages set to the same version as their parent package. https://discuss.python.org/t/allow-package-references-as-version-specifiers/19226/17 has a suggestion on how to do that.

Having such info on https://typing.readthedocs.io/en/latest/source/stubs.html#distribution may be helpful.