Add a new translation
  Documentation/translations/zh_CN/maintainer/modifying-patches.rst
and link it to zh_CN/maintainer/index.rst
Signed-off-by: Wu XiangCheng <bobwxc@email.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
Link: https://lore.kernel.org/r/35e6878cb634db61c573fc7fdc69ef4c5d8ae31c.1621243426.git.bobwxc@email.cnSigned-off-by: Jonathan Corbet <corbet@lwn.net>