Add support for mermaid

[xettri]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and discussions and couldn’t find anything or linked relevant results below
• I made sure the docs are up to date
• I included tests (or that’s not needed)

Description of changes

TODO

[xettri]

I checked this, but it doesn’t appear to be supported natively by react-markdown. If there’s any workaround available in react-markdown, it would be appreciated.

[remcohaszing]

It’s a deliberate choice to not support such features out of the box. You can use rehype-mermaid if you want to render mermaid code blocks as diagrams.

[github-actions]

Hi team! Could you describe why this has been marked as external?

Thanks,
— bb

[ChristianMurphy]

Welcome @xettri 👋
And thanks for sharing.

This doesn't align with react-markdown's design.
Non-standard and semi-standard markdown (like mermaid on code blocks) are handled through plugins (more on that here https://unifiedjs.com/learn/)
This keeps core small and focused, and allows a lot of flexibility.

There is an existing plugin that adds mermaid support which can be used with react-markdown https://github.com/remcohaszing/rehype-mermaid
I'd recommend using that, or if you can't share your experience in the rehype-mermaid issue tracker