reproduce:
        # https://github.com/AsahiLinux/linux/commit/b9472ab57f36e3a0b6c154e4d1374e840676cbdc
        git remote add asahilinux https://github.com/AsahiLinux/linux
        git fetch --no-tags asahilinux bits/005-maintainers
        git checkout b9472ab57f36e3a0b6c154e4d1374e840676cbdc
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # install Sphinx 2.4.4
        make htmldocs