[Docs Site] Bump mermaid from 11.8.1 to 11.9.0 (cloudflare#23811)

Bumps [mermaid](https://github.com/mermaid-js/mermaid) from 11.8.1 to 11.9.0.
- [Release notes](https://github.com/mermaid-js/mermaid/releases)
- [Commits](https://github.com/mermaid-js/mermaid/compare/[email protected]@11.9.0)

---
updated-dependencies:
- dependency-name: mermaid
  dependency-version: 11.9.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

package-lock.json

@@ -85,7 +85,7 @@
 		"mdast-util-from-markdown": "2.0.2",
 		"mdast-util-mdx": "3.0.0",
 		"mdast-util-mdx-expression": "2.0.1",
-		"mermaid": "11.8.1",
+		"mermaid": "11.9.0",
 		"micromark-extension-mdxjs": "3.0.0",
 		"nanostores": "1.0.1",
 		"node-html-parser": "7.0.1",