code: public DateTimeFormatterBuilder appendChronologyText(TextStyle textStyle) {
          Jdk8Methods.requireNonNull(textStyle, "textStyle");
          appendInternal(new ChronoPrinterParser(textStyle));
          return this;
      }
docs: Appends the chronology ID, such as 'ISO' or 'ThaiBuddhist', to the formatter.
  <p>
  This appends an instruction to format/parse the chronology ID to the builder.
  <p>
  During printing, the chronology is obtained using a mechanism equivalent
  to querying the temporal with {@link TemporalQueries#chronology()}.
  It will be printed using the result of {@link Chronology#getId()}.
  If the chronology cannot be obtained then an exception is thrown unless the
  section of the formatter is optional.
  <p>
  During parsing, the chronology is parsed and must match one of the chronologies
  in {@link Chronology#getAvailableChronologies()}.
  If the chronology cannot be parsed then an exception is thrown unless the
  section of the formatter is optional.
  The parser uses the {@linkplain #parseCaseInsensitive() case sensitive} setting.
  
  @return this, for chaining, not null