feat: support for mermaid diagrams

[LachlanNewman]

This PR is to support rendering mermaid diagrams.

Closes #124.

[simonhaenisch]

Cool thanks, however could I ask that you turn your code into a marked-mermaid extension (i.e. npm package)? See https://marked.js.org/using_pro#extensions and https://marked.js.org/using_advanced#extensions. Then you can just pass it into marked_extensions via config (after #140 is merged).

If the module is small enough and doesn't have a performance impact, then we can add it by default as well.

[giuliboy]

+1
would love having mermaid support.
currently we're using an overengineered Pandoc (md->latex->pdf) pipeline that is un-maintainable and we're looking for an alternative service that provides the same UX and similar results for the use case of bringing our Azure DevOps markdown wikis to PDF.

[simonhaenisch]

@LachlanNewman did you ever get around to publishing a mermaid extension for marked? If not, would you mind if I do it based on your code?

[LachlanNewman]

@simonhaenisch sure go ahead I've just reopened the pull request so we can look at implementing this together. Last time I ran into an issue with passing the extension that's actually the reason I was going to try to put this in the library rather than make it an extension

[LachlanNewman]

@simonhaenisch could we have this extension built in. because it requires loading the mermaid executable into the browsers to render the diagrams?

[neiroc]

any news about this feature?