docs/zh_CN: remove two inconsistent spaces

The spaces on the left and right of texts should be consistent.
Remove these redundent spaces.

Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240427053703.2339727-1-dzm91@hust.edu.cn