Fix messages and descriptions for what-if error codes (Azure#11453)

* Fix what-if error code descriptions

* Add a missing new line

documentation/Semantic-and-Model-Violations-Reference.md

@@ -90,8 +90,8 @@ This document lists the set of automated rules that can be validated against swa
 | [REQUEST_VALIDATION_ERROR](#REQUEST_VALIDATION_ERROR) | [OAV109](#REQUEST_VALIDATION_ERROR) |
 | [RESPONSE_STATUS_CODE_NOT_IN_EXAMPLE](#RESPONSE_STATUS_CODE_NOT_IN_EXAMPLE) | [OAV111](#RESPONSE_STATUS_CODE_NOT_IN_EXAMPLE) |
 | [ROUNDTRIP_INCONSISTENT_PROPERTY](#ROUNDTRIP_INCONSISTENT_PROPERTY) | |
-| [ROUNDTRIP_ADDITIONAL_PROPERTY](#ROUNDTRIP_ADDITIONAL_PROPERTY) | |
 | [ROUNDTRIP_MISSING_PROPERTY](#ROUNDTRIP_MISSING_PROPERTY) | |
+| [ROUNDTRIP_ADDITIONAL_PROPERTY](#ROUNDTRIP_ADDITIONAL_PROPERTY) | |
 
 
 ### Validation Warnings
@@ -811,7 +811,7 @@ This document lists the set of automated rules that can be validated against swa
 **How to fix the violation**: If the property is a read-only, update the swagger definition for this property to mark it as "readOnly": true. Alternatively, keep the property in the GET schema but remove it from the PUT schema. If the property has a default value, update the Swagger definition for this property to mark it with "default": <default value> annotation.
 
 
-### <a name="ROUNDTRIP_ADDITIONAL_PROPERTY" />ROUNDTRIP_ADDITIONAL_PROPERTY
+### <a name="ROUNDTRIP_MISSING_PROPERTY" />ROUNDTRIP_MISSING_PROPERTY
 
 **Output Message**: The property is present in the PUT request but is either never returned in the GET response or is returned with a null value. If this is a property that carries a secret such as a password, update the Swagger definition to mark it with the "x-ms-secret": true annotation.
 
@@ -820,10 +820,10 @@ This document lists the set of automated rules that can be validated against swa
 **How to fix the violation**: Mark the property definition with the "x-ms-secret": true annotation if the property is a secret.
 
 
-### <a name="ROUNDTRIP_MISSING_PROPERTY" />ROUNDTRIP_MISSING_PROPERTY
+### <a name="ROUNDTRIP_ADDITIONAL_PROPERTY" />ROUNDTRIP_ADDITIONAL_PROPERTY
 
 **Output Message**: The property is returned in the GET response, but it is not declared in the PUT request. If it is a read-only property, update the swagger definition for this property to mark it as \"readOnly\": true. Alternatively, keep the property in the GET schema but remove it from the PUT schema. If the property has a default value, update the Swagger definition for this property to mark it with \"default\": <default value> annotation.
 
-**Description**: The property was in the PUT request, but it is returned in the subsequent GET response. This implies that the property is read-only or has a default value.
+**Description**: The property was not in the PUT request, but it is returned in the subsequent GET response. This implies that the property is read-only or has a default value.
 
 **How to fix the violation**: If the property is a read-only, update the swagger definition for this property to mark it as "readOnly": true. Alternatively, keep the property in the GET schema but remove it from the PUT schema. If the property has a default value, update the Swagger definition for this property to mark it with "default": <default value> annotation.