Stop trying to redo when history runs out.

worldedit-core/src/main/java/com/sk89q/worldedit/command/HistoryCommands.java

@@ -110,6 +110,7 @@ public class HistoryCommands {
                 worldEdit.flushBlockBag(player, redone);
             } else {
                 player.printError("Nothing left to redo.");
+                break;
             }
         }
     }