docs: protected I_CmsSearchDocument appendCategories(
          I_CmsSearchDocument document,
          CmsObject cms,
          CmsResource resource,
          I_CmsExtractionResult extractionResult,
          List<CmsProperty> properties,
          List<CmsProperty> propertiesSearched)
      throws CmsException {
  
          CmsCategoryService categoryService = CmsCategoryService.getInstance();
          document.addCategoryField(categoryService.readResourceCategories(cms, resource));
  
          return document;
      }