reproduce:
        git remote add clk https://git.kernel.org/pub/scm/linux/kernel/git/clk/linux.git
        git fetch clk clk-next
        git checkout clk/clk-next
        b4 shazam https://lore.kernel.org/r/20241009205619.16250-3-andreas@kemnade.info
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # install Sphinx 2.4.4
        make htmldocs