code: public <V, T extends Enum & Option> OptionsMapper string(final T option, final String value) {
          return string(option, value, null);
      }
docs: Shortcut version of {@link #string(Enum, String, Function)}. Used when default converters could be used.
  
  @param option option
  @param value  value string (could be null)
  @param <V>    helper value type
  @param <T>    helper option type
  @return mapper instance for chained calls