docs: public DateTimeFormatterBuilder appendLiteral(String text) {
          if (text == null) {
              throw new IllegalArgumentException("Literal must not be null");
          }
          switch (text.length()) {
              case 0:
                  return this;
              case 1:
                  return append0(new CharacterLiteral(text.charAt(0)));
              default:
                  return append0(new StringLiteral(text));
          }
      }