docs/zh_CN: update co-developed-by info after English version

docs/zh_CN: update co-developed-by info after English version

commit 4ec6432a3139 ("docs: Clarify the usage and sign-off requirements for Co-developed-by")
give more info of co-developed-by tag usage. update Chinese docs to
follow it.

Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Harry Wei <harryxiyou@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Tom Levy <tomlevy93@gmail.com>
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>