reproduce:
        git remote add char-misc https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
        git fetch char-misc char-misc-testing
        git checkout char-misc/char-misc-testing
        b4 shazam https://lore.kernel.org/r/20241210054055.144813-2-ajd@linux.ibm.com
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # install Sphinx 2.4.4
        make htmldocs