Update readme example

Author: Leon Michalski

packages/aws-cdk-lib/aws-stepfunctions/README.md

@@ -843,16 +843,22 @@ map.itemProcessor(definition);
 When using `JSONata`, the `itemSelector` property in a Map state can be specified in one of two ways. You can provide a valid JSON object containing JSONata expressions for each value:
 
 ```ts
-itemSelector: {
-  id: '{% $states.context.Map.Item.Value.id %}',
-  status: '{% $states.context.Map.Item.Value.status %}',
-}
+const map = new sfn.Map(this, 'Map State', {
+  maxConcurrency: 1,
+  itemSelector: {
+    id: '{% $states.context.Map.Item.Value.id %}',
+    status: '{% $states.context.Map.Item.Value.status %}',
+  }
+});
 ```
 
 Alternatively, you can use the `jsonataItemSelector` field to directly supply a JSONata string that evaluates to a complete JSON object:
 
 ```ts
-jsonataItemSelector: '{% {\"id\": $states.input.id, \"status\": $states.input.status} %}'
+const map = new sfn.Map(this, 'Map State', {
+  maxConcurrency: 1,
+  jsonataItemSelector: '{% {\"id\": $states.input.id, \"status\": $states.input.status} %}'
+});
 ```
 
 To define a distributed `Map` state set `itemProcessors` mode to `ProcessorMode.DISTRIBUTED`.