Support for mermaid.js

[dkadiog]

Feature Request

Feature Suggestion

As github supports mermaid.js diagrams in markdown, it would be nice to also support it in the generated html files.

Context

writing mermaid diagrams in the adr markdowns using Githubs mermaid diagrams, should be rendered as diagram in the html files generated by "log4brains build".

I tryed to make it work by writing accoring the sample on mermaid.js direclty in the markdoww adr.

<pre class="mermaid">
  graph LR
      A --- B
      B-->C[fa:fa-ban forbidden]
      B-->D(fa:fa-spinner);
</pre>
<script src="https://cdnjs.cloudflare.com/ajax/libs/mermaid/9.2.1/mermaid.min.js"/>
<script>
  mermaid.initialize({ startOnLoad: true });
</script>

works for html files in gh-pages but editing the mardkown with a previewer locally wouldnt render the diagram correctly.
So by writing mermaid markdown syntax, like following, the rendered index file should render something like above.

```mermaid
graph TD;
    A-->B;
    A-->C;
    B-->D;
    C-->D;
\```