Bump path-to-regexp and astro in /docs (#840)

Removes [path-to-regexp](https://github.com/pillarjs/path-to-regexp). It's no longer used after updating ancestor dependency [astro](https://github.com/withastro/astro/tree/HEAD/packages/astro). These dependencies need to be updated together.


Removes `path-to-regexp`

Updates `astro` from 4.15.6 to 4.15.8
- [Release notes](https://github.com/withastro/astro/releases)
- [Changelog](https://github.com/withastro/astro/blob/main/packages/astro/CHANGELOG.md)
- [Commits](https://github.com/withastro/astro/commits/astro@4.15.8/packages/astro)

---
updated-dependencies:
- dependency-name: path-to-regexp
  dependency-type: indirect
- dependency-name: astro
  dependency-type: direct:production
...

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docs/package.json

@@ -12,7 +12,7 @@
   "dependencies": {
     "@astrojs/check": "^0.9.3",
     "@astrojs/starlight": "^0.27.1",
-    "astro": "^4.15.3",
+    "astro": "^4.15.8",
     "sharp": "^0.32.5",
     "typescript": "^5.6.2"
   }