docs: private static String getPluralCaseOpenString(SoyMsgPluralCaseSpec pluralCaseSpec) {
      String icuCaseName =
          (pluralCaseSpec.getType() == SoyMsgPluralCaseSpec.Type.EXPLICIT)
              ? "=" + pluralCaseSpec.getExplicitValue()
              : pluralCaseSpec.getType().name().toLowerCase();
      return icuCaseName + "{";
    }