This is just to track the issue, initially reported here:

https://github.com/python/python-docs-theme/issues/63

Then discussed here:

https://github.com/python/cpython/pull/23827#issuecomment-753598860

Then reverted:

- in 3.8 https://github.com/python/cpython/pull/24093
- in 3.9 https://github.com/python/cpython/pull/24092

I edited the revert to keep only relevant parts, as only a few bits of the commit were causing troubles.

Issue is: Sphinx 2 and Sphinx 3 have incompatible handling of backslahes, fixing them for Sphinx 3 in Python 3.10, then backporting to 3.8 and 3.9 which use Sphinx 2 caused an issue: `\n` for example are rendered as `n`, easy to notice in the documentaion of print:

    print(*objects, sep=' ', end='n', file=sys.stdout, flush=False)¶

As migration to Sphinx 3 was hard (done for Python 3.10 documentation), it won't be backported to 3.8 and 3.9, which will still be built using Sphinx 2, so some bits had to be reverted for the doc to display the backslash of `\n`.