reproduce:
        git checkout linus/master
        b4 shazam https://lore.kernel.org/r/20250606153440.865808-4-alexandre.chartre@oracle.com
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # install Sphinx 3.4.3
        make htmldocs