chore(deps): bump @astrojs/starlight from 0.39.3 to 0.40.0 in /docs

Bumps [@astrojs/starlight](https://github.com/withastro/starlight/tree/HEAD/packages/starlight) from 0.39.3 to 0.40.0.
- [Release notes](https://github.com/withastro/starlight/releases)
- [Changelog](https://github.com/withastro/starlight/blob/main/packages/starlight/CHANGELOG.md)
- [Commits](https://github.com/withastro/starlight/commits/@astrojs/starlight@0.40.0/packages/starlight)

---
updated-dependencies:
- dependency-name: "@astrojs/starlight"
  dependency-version: 0.40.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

docs/package.json

@@ -18,7 +18,7 @@
 		"check": "biome check --write"
 	},
 	"dependencies": {
-		"@astrojs/starlight": "0.39.3",
+		"@astrojs/starlight": "0.40.0",
 		"astro": "6.3.8",
 		"sharp": "0.34.5",
 		"vite": "7.3.5"