docs(iot): add example import (aws#19478)

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packages/@aws-cdk/aws-iot/README.md

@@ -36,6 +36,7 @@ Import it into your code:
 
 ```ts nofixture
 import * as iot from '@aws-cdk/aws-iot';
+import * as actions from '@aws-cdk/aws-iot-actions-alpha';
 ```
 
 ## `TopicRule`