chore(deps): bump the npm_and_yarn group across 1 directory with 4 updates

Bumps the npm_and_yarn group with 3 updates in the /docs directory: [next](https://github.com/vercel/next.js), [dompurify](https://github.com/cure53/DOMPurify) and [mermaid](https://github.com/mermaid-js/mermaid).


Updates `next` from 15.3.3 to 15.5.6
- [Release notes](https://github.com/vercel/next.js/releases)
- [Changelog](https://github.com/vercel/next.js/blob/canary/release.js)
- [Commits](https://github.com/vercel/next.js/compare/v15.3.3...v15.5.6)

Updates `dompurify` from 3.1.6 to 3.3.0
- [Release notes](https://github.com/cure53/DOMPurify/releases)
- [Commits](https://github.com/cure53/DOMPurify/compare/3.1.6...3.3.0)

Updates `mermaid` from 10.9.3 to 10.9.5
- [Release notes](https://github.com/mermaid-js/mermaid/releases)
- [Commits](https://github.com/mermaid-js/mermaid/compare/v10.9.3...v10.9.5)

Updates `mermaid` from 10.9.3 to 11.12.1
- [Release notes](https://github.com/mermaid-js/mermaid/releases)
- [Commits](https://github.com/mermaid-js/mermaid/compare/v10.9.3...v10.9.5)

Updates `micromatch` from 4.0.5 to 4.0.8
- [Release notes](https://github.com/micromatch/micromatch/releases)
- [Changelog](https://github.com/micromatch/micromatch/blob/master/CHANGELOG.md)
- [Commits](https://github.com/micromatch/micromatch/compare/4.0.5...4.0.8)

---
updated-dependencies:
- dependency-name: next
  dependency-version: 15.5.6
  dependency-type: direct:production
  dependency-group: npm_and_yarn
- dependency-name: dompurify
  dependency-version: 3.3.0
  dependency-type: indirect
  dependency-group: npm_and_yarn
- dependency-name: mermaid
  dependency-version: 10.9.5
  dependency-type: indirect
  dependency-group: npm_and_yarn
- dependency-name: mermaid
  dependency-version: 11.12.1
  dependency-type: indirect
  dependency-group: npm_and_yarn
- dependency-name: micromatch
  dependency-version: 4.0.8
  dependency-type: indirect
  dependency-group: npm_and_yarn
...

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

docs/package.json

@@ -8,9 +8,9 @@
   "dependencies": {
     "@vercel/analytics": "^1.1.1",
     "docsgpt-react": "^0.5.1",
-    "next": "^15.3.3",
-    "nextra": "^2.13.2",
-    "nextra-theme-docs": "^2.13.2",
+    "next": "^15.5.6",
+    "nextra": "^4.6.0",
+    "nextra-theme-docs": "^4.6.0",
     "react": "^18.2.0",
     "react-dom": "^18.2.0"
   }