Merge tag 'docs-6.2-fixes' of git://git.lwn.net/linux

Pull documentation fixes from Jonathan Corbet:
 "Three documentation fixes (or rather two and one warning):

   - Sphinx 6.0 broke our configuration mechanism, so fix it

   - I broke our configuration for non-Alabaster themes; Akira fixed it

   - Deprecate Sphinx < 2.4 with an eye toward future removal"

* tag 'docs-6.2-fixes' of git://git.lwn.net/linux:
  docs/conf.py: Use about.html only in sidebar of alabaster theme
  docs: Deprecate use of Sphinx < 2.4.x
  docs: Fix the docs build with Sphinx 6.0