reproduce:
        git checkout 4001bda0cc911fcdd3dde36963a17f4eac173d7d
        b4 shazam https://lore.kernel.org/r/20251223105604.12675-3-arun.muthusamy@gaisler.com
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs