docs: protected String optionDisplayString(final String opt, boolean extended) {
          StringBuffer stringBuffer = new StringBuffer();
          stringBuffer.append("-").append(opt);
          Option option = getOption(opt);
          if(null!=option) {
              if (option.getLongOpt() != null) {
                  stringBuffer.append("/--");
                  stringBuffer.append(option.getLongOpt());
              }
              if(option.getArgName()!=null && extended){
                  stringBuffer.append(" <");
                  stringBuffer.append(option.getArgName());
                  stringBuffer.append(">");
              }
          }
          return stringBuffer.toString();
      }