Changelog: document `Py_AtExit` requirement change that the interpreter must be initialized

Documentation

Python 3.12 has commit 2ad2bd8b14505ee92600e7988379cfac63086dab which now requires that the interpreter be initialized before calling Py_AtExit. Please add a retroactive note to the changelog for 3.12 and a new one to 3.13 (for those who don't go back to read the 3.12 changelogs) about this new change.

The API docs might also want to mention it too.

首先阅读提交 2ad2bd8b14505ee92600e7988379cfac63086dab，并找到 Python 3.12 和 3.13 的 changelog 部分。在两个 changelog 中记录：调用 Py_AtExit 前必须初始化解释器；然后检查 API 文档，以确定是否也应在那里注明相同的要求。