Add @Override annotations, remove unused imports,

add some copyright headers, some tab->ws


git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@21654 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/MarkupText.java

@@ -228,6 +228,7 @@ public class MarkupText extends AbstractMarkupText {
     /**
      * Returns the fully marked-up text.
      */
+    @Override
     public String toString() {
         if(tags.isEmpty())
             return text;    // the most common case