Upgrade: Bump mermaid from 9.3.0 to 9.4.0

Bumps [mermaid](https://github.com/mermaid-js/mermaid) from 9.3.0 to 9.4.0.
- [Release notes](https://github.com/mermaid-js/mermaid/releases)
- [Changelog](https://github.com/mermaid-js/mermaid/blob/develop/CHANGELOG.md)
- [Commits](https://github.com/mermaid-js/mermaid/compare/v9.3.0...v9.4.0)

---
updated-dependencies:
- dependency-name: mermaid
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

package.json

@@ -32,7 +32,7 @@
     "esbuild": "^0.17.0",
     "jquery": "^3.6.0",
     "markdown-it-footnote": "^3.0.3",
-    "mermaid": "^9.3.0",
+    "mermaid": "^9.4.0",
     "vuepress-plugin-mermaidjs": "^2.0.0-beta.2"
   }
 }