Deprecate support classes for Sun's JDK HTTP server

Issue: SPR-17143

spring-core/src/main/java/org/springframework/lang/UsesSunHttpServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2018 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.
@@ -28,7 +28,9 @@ import java.lang.annotation.Target;
  *
  * @author Stephane Nicoll
  * @since 4.1
+ * @deprecated as of 5.1, along with Spring's Sun HTTP Server support classes
  */
+@Deprecated
 @Retention(RetentionPolicy.CLASS)
 @Target({ElementType.METHOD, ElementType.CONSTRUCTOR, ElementType.TYPE})
 @Documented