rustup*: add Chinese translation

[Clathweppes]

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: #

[CLAassistant]

All committers have signed the CLA.

[Managor]

In the future I recommend splitting these into 5 pages per PR so that the reviewers can look through these in bite sized chunks.

[Clathweppes]

Thanks for the suggestion. I’ll do that in future PRs.

[Clathweppes]

Commit f49eec7 updates the link in rustup-man.md in the same way as PR #19691.