reproduce:
        git checkout 4ae12d8bd9a830799db335ee661d6cbc6597f838
        b4 shazam https://lore.kernel.org/r/20260309205125.293148-5-lkml@antheas.dev
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs