For attribute is not actually required

Issue: SPR-14287

spring-webmvc/src/main/java/org/springframework/web/servlet/tags/form/LabelTag.java

 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2016 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.
@@ -25,8 +25,6 @@ import org.springframework.util.StringUtils;
  * Databinding-aware JSP tag for rendering an HTML '{@code label}' element
  * that defines text that is associated with a single form element.
  *
- * <p>The {@link #setFor(String) 'for'} attribute is required.
- *
  * <p>See the "formTags" showcase application that ships with the
  * full Spring distribution for an example of this class in action.
  *