Displays no permission required as None instead of null

src/main/java/net/knarcraft/bookswithoutborders/command/CommandBooksWithoutBorders.java

@@ -104,6 +104,9 @@ public class CommandBooksWithoutBorders implements TabExecutor {
                 String commandInfo = "\n" + getCommandColor() + pluginCommand.getUsage().replace("<command>",
                         pluginCommand.getName()) + ": " + getSuccessColor() + pluginCommand.getDescription();
                 if (sender.hasPermission("bookswithoutborders.admin")) {
+                    if (permission == null) {
+                        permission = "None";
+                    }
                     commandInfo += getCommandColor() + " {" + permission + "}";
                 }
                 sender.sendMessage(commandInfo);