chore: update dependency @astrojs/starlight to ^0.23.1

Author: renovate[bot]

package.json

@@ -25,7 +25,7 @@
   },
   "devDependencies": {
     "@astrojs/check": "^0.5.10",
-    "@astrojs/starlight": "^0.21.5",
+    "@astrojs/starlight": "^0.23.1",
     "@biomejs/biome": "^1.5.3",
     "@changesets/changelog-github": "^0.5.0",
     "@changesets/cli": "^2.27.1",