Add Chinese translation for the sidebar menu links

[fanenr]

PR Checklist

• The commit message follows guidelines for NexT.
• The changes have been tested (for bug fixes / features).
• Docs in NexT website have been added / updated (for features).

PR Type

• Bugfix.
• Feature.
• Improvement.
• Code style update (formatting, linting).
• Refactoring (no functional changes).
• Documentation.
• Translation.
• Other... Please describe:

What is the current behavior?

Issue resolved:

What is the new behavior?

• Link to demo site with this changes:
• Screenshots with this changes:

How to use?

In NexT _config.yml:

[welcome]

Thanks so much for opening your first PR here!

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[njzjz]

It seems the theme does not use this key. If you use it on your website, you can create your customized language file. See https://github.com/next-theme/hexo-theme-next/tree/master/languages#override-default-translations

[fanenr]

It seems the theme does not use this key. If you use it on your website, you can create your customized language file. See https://github.com/next-theme/hexo-theme-next/tree/master/languages#override-default-translations

Thank you :)