You've linked to the release notes for Python 3.11 final wheels - it just starts out saying that the previous release had beta wheels.
Similarly, the release notes for Python 3.12 final wheels are at https://pillow.readthedocs.io/en/stable/releasenotes/10.1.0.html#python-3-12 and mention beta wheels in the previous release.

From what I can see, we've never announced beta wheels in the release they're in.

We can start that tradition if you want though.