docs: private static Map<String, Integer> appendDisplayNames(final Calendar cal, final Locale locale, final int field, final StringBuilder regex) {
  		final Map<String, Integer> values = new HashMap<>();
  
  		final Map<String, Integer> displayNames = cal.getDisplayNames(field, Calendar.ALL_STYLES, locale);
  		final TreeSet<String> sorted = new TreeSet<>(LONGER_FIRST_LOWERCASE);
  		for (final Map.Entry<String, Integer> displayName : displayNames.entrySet()) {
  			final String key = displayName.getKey().toLowerCase(locale);
  			if (sorted.add(key)) {
  				values.put(key, displayName.getValue());
  			}
  		}
  		for (final String symbol : sorted) {
  			simpleQuote(regex, symbol).append('|');
  		}
  		return values;
  	}