docs: enable chinese link

[naomi-lgbt]

Checklist:

• I have read freeCodeCamp's contribution guidelines.
• My pull request has a descriptive title (not a vague title like Update index.md)
• My pull request targets the main branch of freeCodeCamp.
• All the files I changed are in the same world language, for example: only English changes, or only Chinese changes, etc.

Closes #XXXXX

Enables the Chinese link in the translation menu. The files are not yet 100% translated, but the two that focus on our translation flow are. Having these available could potentially increase our translation contributions.

[gitpod-io]

[raisedadead]

I think we should add Portuguese which has hit 100% (translated, not-proofread) as well.

[naomi-lgbt]

Sure - I'll need to modify the workflow to allow those files to be downloaded, migrate the English files into a Portuguese folder (to avoid 404s until translations are approved) and add the link.

Given the scope, should I do that in a separate PR so as to avoid blocking this one?

[raisedadead]

Sounds good.