Improved Javadoc navigation (similar to Scaladoc).

h2/src/tools/org/h2/build/doc/LinkChecker.java

@@ -80,7 +80,7 @@ public class LinkChecker {
             if (!link.startsWith("http") && !link.endsWith("h2.pdf")
                     && link.indexOf("_ja.") < 0) {
                 if (targets.get(link) == null) {
-                    errors.add(links.get(link) + ": missing link " + link);
+                    errors.add(links.get(link) + ": link missing " + link);
                 }
             }
         }