chore: bump next in /docs in the npm_and_yarn group across 1 directory (#2277)

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

docs/package.json

@@ -86,7 +86,7 @@
     "fumadocs-typescript": "4.0.6",
     "fumadocs-ui": "15.5.4",
     "import-in-the-middle": "^1.15.0",
-    "next": "15.5.7",
+    "next": "15.5.9",
     "nodemailer": "^7.0.11",
     "partykit": "^0.0.115",
     "pg": "^8.16.3",