[Gardening] Fix formatting when diagnosing with attr_must_be_used_on_class_instance
[Gardening] Fix formatting when diagnosing with attr_must_be_used_on_class_instance

JGiola/swift,JGiola/swift,glessard/swift,glessard/swift,roambotics/swift,benlangmuir/swift,glessard/swift,apple/swift,glessard/swift,apple/swift,roambotics/swift,benlangmuir/swift,benlangmuir/swift,apple/swift,apple/swift,apple/swift,glessard/swift,benlangmuir/swift,JGiola/swift,roambotics/swift,benlangmuir/swift,roambotics/swift,JGiola/swift,apple/swift,roambotics/swift,JGiola/swift,benlangmuir/swift,JGiola/swift,glessard/swift,roambotics/swift