[Feature] Add new message types & error codes (#2562)

* Add new message types & error codes

* add role subscription system channel flags and message property

src/Discord.Net.WebSocket/Entities/Messages/SocketMessage.cs

@@ -78,6 +78,9 @@ namespace Discord.WebSocket
         /// <inheritdoc/>
         public MessageType Type { get; private set; }
 
+        /// <inheritdoc />
+        public MessageRoleSubscriptionData RoleSubscriptionData { get; private set; }
+
         /// <summary>
         ///     Returns all attachments included in this message.
         /// </summary>
@@ -271,6 +274,15 @@ namespace Discord.WebSocket
 
             if (model.Flags.IsSpecified)
                 Flags = model.Flags.Value;
+
+            if (model.RoleSubscriptionData.IsSpecified)
+            {
+                RoleSubscriptionData = new(
+                    model.RoleSubscriptionData.Value.SubscriptionListingId,
+                    model.RoleSubscriptionData.Value.TierName,
+                    model.RoleSubscriptionData.Value.MonthsSubscribed,
+                    model.RoleSubscriptionData.Value.IsRenewal);
+            }
         }
 
         /// <inheritdoc />