"semantic difference after formatting" in separator char for Firehose

[primdahl]

Having problems getting past this issue in an IoT config for Firehose (done as per https://docs.aws.amazon.com/iot/latest/developerguide/kinesis-firehose-rule-action.html)

➜  rain --version
Rain v1.23.0 darwin/arm64
➜  rain fmt separator.yaml
semantic difference after formatting:
(|) Resources:
(|)   IoTStateRule:
(|)     Properties:
(|)       TopicRulePayload:
(|)         Actions:
(|)           [0]:
(|)             Firehose:
(>)               Separator: ""

➜  cat separator.yaml
AWSTemplateFormatVersion: "2010-09-09"

Resources:
  IoTStateRule:
    Type: AWS::IoT::TopicRule
    Properties:
      TopicRulePayload:
        Sql: SELECT * FROM 'test'
        AwsIotSqlVersion: "2016-03-23"
        Actions:
        - Firehose:
            DeliveryStreamName: test-stream
            RoleArn: arn:aws:iam::123456789012:role/test-role
            Separator: "\n"%