Bump @next/mdx from 14.2.6 to 15.1.6

Bumps [@next/mdx](https://github.com/vercel/next.js/tree/HEAD/packages/next-mdx) from 14.2.6 to 15.1.6.
- [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/commits/v15.1.6/packages/next-mdx)

---
updated-dependencies:
- dependency-name: "@next/mdx"
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

package.json

@@ -22,7 +22,7 @@
     "@hackclub/meta": "1.1.32",
     "@hackclub/theme": "^0.3.3",
     "@mdx-js/loader": "^1.6.22",
-    "@next/mdx": "^14.1.0",
+    "@next/mdx": "^15.1.6",
     "@octokit/auth-app": "^6.0.1",
     "@octokit/core": "^5.1.0",
     "@octokit/rest": "^20.0.2",

yarn.lock

@@ -1428,10 +1428,10 @@
   dependencies:
     glob "10.3.10"
 
-"@next/mdx@^14.1.0":
-  version "14.2.6"
-  resolved "https://registry.npmjs.org/@next/mdx/-/mdx-14.2.6.tgz"
-  integrity sha512-59jhA506DXouG5T1lUjG8TAYGIQNia6hDuDgRIJwWfOEzgDvIOZHL3/oUGFH9BS2/Y75a9y0l65Lz0aMvUEWeg==
+"@next/mdx@^15.1.6":
+  version "15.1.6"
+  resolved "https://registry.yarnpkg.com/@next/mdx/-/mdx-15.1.6.tgz#c014aa1b0448304d977239bbcd581f797028b956"
+  integrity sha512-jt9b9ayY8z3F/oQa2YCK7NugxY6ttAiJ8Eu29OTwwW5rcYMjXohIRaqsSrgFWhCFkJA6/EccKO+1ApocCZnn5A==
   dependencies:
     source-map "^0.7.0"