doc-guide: add help documentation checktransupdate.rst

This commit adds help documents - doc-guide/checktransupdate.rst
and zh_CN/doc-guide/checktransupdate.rst for scripts/checktransupdate.py
, including English and Chinese versions

Signed-off-by: Dongliang Mu <dzm91@hust.edu.cn>
Reviewed-by: Yanteng Si <siyanteng@loongson.cn>
[jc: fixed missing title problem in the new file]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240719041400.3909775-3-dzm91@hust.edu.cn