docs: private static void convertPluralPartHelper(
        Builder<SoyMsgPart> newMsgPartsBuilder,
        StringBuilder currRawTextSb,
        SoyMsgPluralPart origPluralPart) {
  
      currRawTextSb.append(
          getPluralOpenString(origPluralPart.getPluralVarName(), origPluralPart.getOffset()));
  
      for (Case<SoyMsgPluralCaseSpec> pluralCase : origPluralPart.getCases()) {
        currRawTextSb.append(getPluralCaseOpenString(pluralCase.spec()));
        convertMsgPartsHelper(
            newMsgPartsBuilder, currRawTextSb, pluralCase.parts(), /* isInPlrselPart= */ true);
        currRawTextSb.append(getPluralCaseCloseString());
      }
  
      currRawTextSb.append(getPluralCloseString());
    }