shutdown: add Chinese translation

[search233]

Checklist

• The page(s) are in the correct platform directories: common, linux, osx, windows, sunos, android, etc.
• The page description(s) have links to documentation or a homepage.
• The page(s) follow the content guidelines.
• The page(s) follow the style guide.
• The PR contains at most 5 new pages.
• The PR is authored by me, or has been human-reviewed if it was created with AI or machine translation software.
• The PR title conforms to the recommended templates.
• Version of the command being documented (if known):
• Reference issue: #
• Closes: #

[CLAassistant]

All committers have signed the CLA.

[tldr-bot]

Hello! I've noticed something unusual when checking this PR at commit
b9f0ec50c76ce2aba2ac61ad411bc8e2cdb8a825:

• The page pages.zh/linux/shutdown.md is outdated, based on number of header lines, compared to the English page.
• The page pages.zh/linux/shutdown.md has a see also mention that does not match the one in the English page or the template. Please check the "See also:" translation as well using the translation template or run scripts/set-see-also.py -S.

Is this intended? If so, just ignore this comment. Otherwise, please double-check the commits.