code: public ClassificationModel attachClassification(GraphRewrite event, Rule rule, FileModel fileModel, String classificationText, String description)
      {
          return attachClassification(event, rule, fileModel, IssueCategoryRegistry.DEFAULT, classificationText, description);
      }
docs: Attach a {@link ClassificationModel} with the given classificationText and description to the provided {@link FileModel}.
  If an existing Model exists with the provided classificationText, that one will be used instead.