Fixes issue se-edu#347

Author: dezhanglee

src/seedu/addressbook/commands/Command.java

@@ -41,7 +41,7 @@ public static String getMessageForPersonListShownSummary(List<? extends ReadOnly
      */
     public CommandResult execute() {
         throw new UnsupportedOperationException("This method is to be implemented by child classes");
-    };
+    }
 
     /**
      * Supplies the data the command will operate on.