docs/zh_CN: Improve zh_CN/process/6.Followthrough

Improve language and grammar of zh_CN/process/6.Followthrough.rst

Signed-off-by: Wu XiangCheng <bobwxc@email.cn>
Reviewed-by: Alex Shi <alex.shi@linux.alibaba.com>
Link: https://lore.kernel.org/r/2024bbd647208fcb1c8b3db036e6f492bbdb2464.1614920267.git.bobwxc@email.cn


Signed-off-by: Jonathan Corbet <corbet@lwn.net>