reproduce:
        # https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git/commit/?id=8f115a8869712a4d22aa5218e1765f659af5fb63
        git remote add arnd-playground https://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground.git
        git fetch --no-tags arnd-playground randconfig-7.1-next
        git checkout 8f115a8869712a4d22aa5218e1765f659af5fb63
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs