Fix typo

Websocket -> WebSocket

Author: changeworld

articles/application-gateway/features.md

@@ -94,7 +94,7 @@ The cookie-based session affinity feature is useful when you want to keep a user
 
 For more information, see [How an application gateway works](how-application-gateway-works.md#modifications-to-the-request).
 
-## Websocket and HTTP/2 traffic
+## WebSocket and HTTP/2 traffic
 
 Application Gateway provides native support for the WebSocket and HTTP/2 protocols. There's no user-configurable setting to selectively enable or disable WebSocket support.