Different signup links needed for English vs Chinese docs

[anil-bd]

The main navigation signup button needs to link to different URLs based on language:

English docs (docs.brightdata.com/introduction): Current signup link (no change)
Chinese docs (docs.brightdata.com/cn/introduction): Should link to https://www.bright.cn/?hs_signup=1&utm_source=docs
Currently unable to set language-specific signup links in the main navigation.