Wrong symbol fix (#2438)

src/Discord.Net.Rest/DiscordRestApiClient.cs

@@ -862,7 +862,7 @@ namespace Discord.API
             options = RequestOptions.CreateOrClone(options);
 
             var ids = new BucketIds(webhookId: webhookId);
-            await SendJsonAsync<Message>("PATCH", () => $"webhooks/{webhookId}/{AuthToken}/messages/{messageId}${WebhookQuery(false, threadId)}", args, ids, clientBucket: ClientBucketType.SendEdit, options: options).ConfigureAwait(false);
+            await SendJsonAsync<Message>("PATCH", () => $"webhooks/{webhookId}/{AuthToken}/messages/{messageId}?{WebhookQuery(false, threadId)}", args, ids, clientBucket: ClientBucketType.SendEdit, options: options).ConfigureAwait(false);
         }
 
         /// <exception cref="InvalidOperationException">This operation may only be called with a <see cref="TokenType.Webhook"/> token.</exception>