[pmwiki-users] I would like to create custom markup like github markdown backticks mermaid

[Christopher Cox]

I've been wresting with trying to create working markup for:

```mermaid
(markup language here)
```

It seems to "work", but my sourceblock is empty.

Markup(
     'mermaid2',
     'fulltext',
     '/```mermaid(.*?)```/si',
     "MermaidMarkup"
);

I'm probably missing something easy.  Any hints?