reproduce:
        git remote add openeuler https://gitee.com/openeuler/kernel.git
        git fetch --no-tags openeuler OLK-6.6
        git checkout 29f85d3cff2dfa35ace94d3e4036d5ea456eb859
        make menuconfig
        # enable CONFIG_COMPILE_TEST, CONFIG_WARN_MISSING_DOCUMENTS, CONFIG_WARN_ABI_ERRORS
        # pip install -r Documentation/sphinx/requirements.txt
        make htmldocs