Proposal: add \z as a synonym for \Z in Python REs for standardization

[hugovk (Hugo van Kemenade)]

\z has now been added to the upcoming Python 3.14, just in time for Tuesday’s feature freeze:

• What’s new in Python 3.14 — Python 3.14.0a7 documentation
• python/cpython#133314
• PEP 745 – Python 3.14 Release Schedule | peps.python.org

Thanks @msbrown for raising this and @storchaka for the PR.