reproduce:
        git remote add lee-mfd https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git
        git fetch lee-mfd for-mfd-next
        git checkout lee-mfd/for-mfd-next
        b4 shazam https://lore.kernel.org/r/20231202192536.266885-4-biju.das.jz@bp.renesas.com
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # install Sphinx 2.4.4
        make htmldocs