docs/zh_CN: fix typos in 1.Intro.rst file

Fixed uncapital issues, thanks for Jonathan Neuschäfer, I am insensitive
on captial custom as a non-captial native language reader. Sorry.

Also fix a typo. And replace more colloquial words in Chinese.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>