Merge pull request #220 from ably/before-publish-rule-chat

chat: add error code for before publish rule violations

textile/chat-features.textile

@@ -613,6 +613,14 @@ This section contains error codes that are specific to Chat. If a specific error
 For non-chat-specific codes, the status code for the error should align with the error code. For example, error code @40000@ should hav status code @400@.
 
 <pre>
+  // The message was rejected before publishing by a rule on the chat room.
+  // To be accompanied by status code 422
+  MessageRejectedByBeforePublishRule = 42211
+
+  // The message was rejected before publishing by a moderation rule on the chat room.
+  // To be accompanied by status code 422
+  MessageRejectedByModeration = 42213
+
   // The messages feature failed to attach.
   // To be accompanied with status code 500.
   MessagesAttachmentFailed = 102001