docs(data-modeling): sidebar as a Data Modeling section with Overview first

Sidebar now reads Data Modeling > Overview / Relational data modeling /
MongoDB data modeling, per review.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Author: ankur-arch

apps/docs/content/docs/orm/next/data-modeling/index.mdx

@@ -1,5 +1,5 @@
 ---
-title: Data modeling overview
+title: Overview
 description: Describe the data your application needs with models, primary keys, scalar fields, and relations.
 url: /orm/next/data-modeling
 metaTitle: Data modeling in Prisma Next

apps/docs/content/docs/orm/next/meta.json

@@ -5,8 +5,7 @@
   "pages": [
     "---Introduction---",
     "index",
-
-    "---Guides---",
-    "data-modeling"
+    "---Data Modeling---",
+    "...data-modeling"
   ]
 }