code: public NlsFormatter<?> registerFormatter(NlsFormatterPlugin<?> formatter) {
  
      return registerFormatter(formatter, formatter.getType(), formatter.getStyle());
    }
docs: This method registers the given {@code formatBuilder}.
  
  @param formatter is the {@link NlsFormatterPlugin} to register.
  @return the {@link NlsFormatter} that was registered for the given {@link NlsFormatterPlugin#getType()
  type} and {@link NlsFormatterPlugin#getStyle() style} and is now replaced by the given
  {@code formatter} or {@code null} if no {@link NlsFormatter} was replaced.