Add Mermaid diagram support to Markdown Live Preview

[krishnactive]

This PR adds Mermaid diagram support to the Markdown Live Preview web app.

Changes:

• Add mermaid dependency and update package-lock.json
• Detect mermaid fenced code blocks and render diagrams in the preview
• Preserve Mermaid source in data-mermaid and execute mermaid.render(...)
• Document Mermaid support in README.md

[krishnactive]

@tanabe Please review

[s-celles]

This would be a great feature to have!
Related issues #66 #111

[krishnactive]

This would be a great feature to have! Related issues #66 #111

Review the code

[tanabe]

Thanks everyone for opening PRs and issues. I’ve just deployed support for Mermaid diagrams.

[krishnactive]

Thank you for the support!