Do not BuildRequire python3-sphinxcontrib-httpdomain, it was not needed
As far as I can tell, the package is not used during the build.
The Fedora package seems outdated and has no check.
A comment in the update pull request (opened 2 years ago)
claims the currently packaged version (1.7.0) is incompatible with Sphinx 4.1+.
Upstream issue: https://github.com/readthedocs/sphinx_rtd_theme/issues/1533