## Summary
#19565 made most of the latest Python version constants non-public, but
the script only matched `pub const` declarations. As a result, the daily
Python release sync workflow silently stopped updating those constants.
This PR fixes that.
This PR also cleans up the script a bit (see individual commits for
details).
## Test Plan
Manual testing.
Update available python versions to include CPython 3.15.0a6
Update scripts used to sync pbs releases to account for recent changes
in the repo and to support running on macOS.