suggest a correction

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@7783 71c3de6d-444a-0410-be80-ed276b4c234a

core/src/main/java/hudson/scheduler/CronTab.java

@@ -106,7 +106,8 @@ public final class CronTab {
                     // this rank has a sparse entry.
                     // if we have a sparse rank, one of them better be the left-most.
                     if(i>0)
-                        return "Do you really mean \"every minute\" when you say \""+spec+"\"?";
+                        return "Do you really mean \"every minute\" when you say \""+spec+"\"? "+
+                                "Perhaps you meant \"0 "+spec.substring(spec.indexOf(' ')+1)+"\"";
                     // once we find a sparse rank, upper ranks don't matter
                     return null;
                 }