[ec2_ami_copy] Add return documentation (#32012)

lib/ansible/modules/cloud/amazon/ec2_ami_copy.py

@@ -130,6 +130,14 @@ EXAMPLES = '''
     kms_key_id: arn:aws:kms:us-east-1:XXXXXXXXXXXX:key/746de6ea-50a4-4bcb-8fbc-e3b29f2d367b
 '''
 
+RETURN = '''
+image_id:
+  description: AMI ID of the copied AMI
+  returned: always
+  type: string
+  sample: ami-e689729e
+'''
+
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.ec2 import (boto3_conn, ec2_argument_spec, get_aws_connection_info)