Enable mermaid diagrams rendering in Notebooks

[cmaneu]

Diagrams can be a great explainer of a (Data engineering) process, code or ML process. 

Notebooks already support including Markdown for adding description. And Mermaid is a well-know way to include diagrams in markdown as text. It's used by GitHub. 

It does not work in Fabric Notebooks, and that would be a great addition.

Workaround: Use services like mermaid.live, but then the content of your diagram "travels" outside Fabric tenant. 

[cmaneu]

GitHub blog post about this feature: "Include diagrams in your Markdown files with Mermaid - The GitHub Blog"

[matthew-brewer]

This would be helpful to our team — we are currently using bullet lists, which take longer to read than a diagram, and, realistically, which nobody will take the time to read.