Enable mermaid diagrams in docusaurus (#6957)

# Pull Request

## 📖 Description

Pursuant to [PR comment](#6947 (review)), this enables mermaid diagrams to be displayed with the new docusaurus v3 update.

## ✅ Checklist

### General

<!--- Review the list and put an x in the boxes that apply. -->

- [ ] I have included a change request file using `$ yarn change`
- [ ] I have added tests for my changes.
- [x] I have tested my changes.
- [ ] I have updated the project documentation to reflect my changes.
- [x] I have read the [CONTRIBUTING](https://github.com/microsoft/fast/blob/master/CONTRIBUTING.md) documentation and followed the [standards](/docs/community/code-of-conduct/#our-standards) for this project.

sites/website/docusaurus.config.js

@@ -7,7 +7,13 @@ module.exports = {
     organizationName: "microsoft",
     projectName: "fast",
     onBrokenLinks: "log",
-    themes: [require.resolve("@docusaurus/theme-live-codeblock")],
+    markdown: {
+        mermaid: true,
+    },
+    themes: [
+        require.resolve("@docusaurus/theme-live-codeblock"),
+        "@docusaurus/theme-mermaid",
+    ],
     staticDirectories: ["static"],
     themeConfig: {
         colorMode: {

sites/website/package.json

@@ -35,6 +35,7 @@
     "@docusaurus/module-type-aliases": "^3.2.1",
     "@docusaurus/preset-classic": "^3.2.1",
     "@docusaurus/theme-live-codeblock": "^3.2.1",
+    "@docusaurus/theme-mermaid": "^3.2.1",
     "@docusaurus/types": "^3.2.1",
     "@mdx-js/react": "^3.0.1",
     "@microsoft/api-documenter": "^7.24.2",