feat: add Mermaid diagram capabilities
Adds the ability to render Mermaid diagrams in Markdown pages.
How to test this?
- Add a diagram to any Markdown content file.
- Navigate to the page you've just updated.
- Note: HMR doesn't pick up on Mermaid syntax changes, so you'll need to refresh the page to see the changes.
Example graph:
```mermaid
sequenceDiagram
par Alice to Bob
Alice->>Bob: Go help John
and Alice to John
Alice->>John: I want this done today
par John to Charlie
John->>Charlie: Can we do this today?
and John to Diana
John->>Diana: Can you help us today?
end
end
```
Closes #1445 (closed)
Edited by Paul Gascou-Vaillancourt