Deprecate JettyWebSocketClient in favor of StandardWebSocketClient

JettyWebSocketClient only supported on Jetty 11, to be phased out.

Closes gh-29576

spring-webflux/src/test/java/org/springframework/web/reactive/socket/AbstractWebSocketIntegrationTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2020 the original author or authors.
+ * Copyright 2002-2022 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -91,6 +91,7 @@ abstract class AbstractWebSocketIntegrationTests {
 
 	static Stream<Object[]> arguments() throws IOException {
 
+		@SuppressWarnings("removal")
 		WebSocketClient[] clients = new WebSocketClient[] {
 				new TomcatWebSocketClient(),
 				new JettyWebSocketClient(),