docs: private static String createMessage(String option, Collection<String> matchingOptions)
      {
          StringBuilder buf = new StringBuilder("Ambiguous option: '");
          buf.append(option);
          buf.append("'  (could be: ");
  
          Iterator<String> it = matchingOptions.iterator();
          while (it.hasNext())
          {
              buf.append("'");
              buf.append(it.next());
              buf.append("'");
              if (it.hasNext())
              {
                  buf.append(", ");
              }
          }
          buf.append(")");
  
          return buf.toString();
      }