Bump @markdoc/next.js from 0.3.7 to 0.4.0

Bumps [@markdoc/next.js](https://github.com/markdoc/next.js) from 0.3.7 to 0.4.0.
- [Release notes](https://github.com/markdoc/next.js/releases)
- [Commits](markdoc/next.js@0.3.7...0.4.0)

---
updated-dependencies:
- dependency-name: "@markdoc/next.js"
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

apps/docs/package.json

@@ -13,7 +13,7 @@
     "@algolia/autocomplete-core": "^1.18.1",
     "@headlessui/react": "^2.2.0",
     "@markdoc/markdoc": "^0.4.0",
-    "@markdoc/next.js": "^0.3.7",
+    "@markdoc/next.js": "^0.4.0",
     "@sindresorhus/slugify": "^2.2.1",
     "@tailwindcss/postcss": "^4.0.17",
     "@tailwindcss/typography": "^0.5.16",