ocaml-psmt2-frontend fails to build with Sphinx 6.1.3 in Fedora 39 (currently Rawhide).

The issue detected:
Exception occurred:
  File "/builddir/build/BUILD/psmt2-frontend-0.4.0/sphinx/conf.py", line 222, in setup
    app.add_stylesheet('css/fixes.css')
    ^^^^^^^^^^^^^^^^^^
AttributeError: 'Sphinx' object has no attribute 'add_stylesheet'


For the logs from testing build attempts, see:
https://copr.fedorainfracloud.org/coprs/ksurma/sphinx-6.1.3/package/ocaml-psmt2-frontend/

You can test you package in mock running:

$ mock -r fedora-rawhide-x86_64 --addrepo=https://download.copr.fedorainfracloud.org/results/ksurma/sphinx-6.1.3/fedora-rawhide-x86_64/ --no-clean your.src.rpm
$ mock -r fedora-rawhide-x86_64 --addrepo=https://download.copr.fedorainfracloud.org/results/ksurma/sphinx-6.1.3/fedora-rawhide-x86_64/ shell

Sphinx 6.1.3 will be included in Fedora 39.
Let us know here if you have any questions. Thank you!