(DOCSP-27197): Rename 'task' to 'item' in RQL examples (#2646)

## Pull Request Info

Rename `task` to `item` in RQL examples and generated code samples

### Jira

- https://jira.mongodb.org/browse/DOCSP-27197

### Staged Changes

- [Realm Query
Language](https://docs-mongodbcom-staging.corp.mongodb.com/realm/docsworker-xlarge/docsp-27197-rename-task-rql/realm-query-language/)

### Reminder Checklist

If your PR modifies the docs, you might need to also update some
corresponding
pages. Check if completed or N/A.

- [x] Create Jira ticket for corresponding docs-app-services update(s),
if any
- [x] Checked/updated Admin API
- [x] Checked/updated CLI reference

### Review Guidelines


[REVIEWING.md](https://github.com/mongodb/docs-realm/blob/master/REVIEWING.md)

Author: cbullinger

examples/dart/test/task_project_models_test.dart

@@ -8,7 +8,7 @@ part 'task_project_models_test.g.dart'; // :remove:
 // :uncomment-end:
 
 @RealmModel()
-class _Task {
+class _Item {
   @MapTo("_id")
   @PrimaryKey()
   late ObjectId id;
@@ -27,7 +27,7 @@ class _Project {
   late ObjectId id;
 
   late String name;
-  late List<_Task> tasks;
+  late List<_Item> items;
   int? quota;
 }
 // :snippet-end:

examples/dotnet/Examples/RqlSchemaExamples.cs

@@ -10,7 +10,8 @@ namespace Examples.RqlSchemaExamples
     //  "terms": {
     //   "RqlTask": "Item",
     //   "RqlProject": "Project",
-    //   "RqlTasks": "Items"}
+    //   "RqlTasks": "Items",
+    //   "RqlItems": "Items"}
     // }
     public class RqlTask : RealmObject
     {

examples/kotlin/shared/src/commonTest/kotlin/com/mongodb/realm/realmkmmapp/RQLTest.kt

@@ -1,13 +1,13 @@
 package com.mongodb.realm.realmkmmapp
 
 import io.realm.kotlin.types.RealmList
-import org.mongodb.kbson.ObjectId
 import io.realm.kotlin.types.RealmObject
 import io.realm.kotlin.types.annotations.PrimaryKey
+import org.mongodb.kbson.ObjectId
 
 class RQLTest: RealmTest() {
     // :snippet-start: rql-schema-example
-    class Task(): RealmObject {
+    class Item(): RealmObject {
         @PrimaryKey
         var _id: ObjectId = ObjectId()
         lateinit var name: String
@@ -21,7 +21,7 @@ class RQLTest: RealmTest() {
         @PrimaryKey
         var _id: ObjectId = ObjectId()
         lateinit var name: String
-        lateinit var tasks: RealmList<Task>
+        lateinit var items: RealmList<Item>
         var quota: Int? = null
     }
     // :snippet-end: