docs: improvements and fixes to API route docs (#9197)

General improvements and fixes to docs around API routes

www/apps/book/app/advanced-development/data-models/index/page.mdx

@@ -1,14 +1,14 @@
 export const metadata = {
-  title: `${pageNumber} Data Model Index`,
+  title: `${pageNumber} Data Model Database Index`,
 }
 
 # {metadata.title}
 
-In this chapter, you’ll learn how to define indices on a data model.
+In this chapter, you’ll learn how to define a database index on a data model.
 
-## Define Index on Property
+## Define Database Index on Property
 
-Use the `index` method on a property's definition to define an index.
+Use the `index` method on a property's definition to define a database index.
 
 For example:
 
@@ -36,9 +36,9 @@ In this example, you define an index on the `name` property.
 
 ---
 
-## Define Index on Data Model
+## Define Database Index on Data Model
 
-A data model has an `indexes` method that defines indices on its properties.
+A data model has an `indexes` method that defines database indices on its properties.
 
 The index can be on multiple columns (composite index). For example:
 
@@ -95,7 +95,7 @@ const MyCustom = model.define("my_custom", {
 export default MyCustom
 ```
 
-The index object passed to `indexes` accepts a `where` property that is an object of conditions. The object's key is a property's name, and its value is the condition on that property.
+The index object passed to `indexes` accepts a `where` property whose value is an object of conditions. The object's key is a property's name, and its value is the condition on that property.
 
 In the example above, the composite index is created on the `name` and `age` properties when the `age`'s value is `30`.
 
@@ -130,7 +130,7 @@ A property's value in `where` can be an object having a `$ne` property. `$ne`'s
 
 In the example above, the composite index is created on the `name` and `age` properties when `age`'s value is not `null`.
 
-### Unique Data Model Index
+### Unique Database Index
 
 The object passed to `indexes` accepts a `unique` property indicating that the created index must be a unique index.