_createPopup() {
    const { data } = this;

    const popup = (this.#popupElement = new PopupAnnotationElement({
      data: {
        color: data.color,
        titleObj: data.titleObj,
        modificationDate: data.modificationDate,
        contentsObj: data.contentsObj,
        richText: data.richText,
        parentRect: data.rect,
        borderStyle: 0,
        id: `popup_${data.id}`,
        rotation: data.rotation,
      },
      parent: this.parent,
      elements: [this],
    }));
    this.parent.div.append(popup.render());
  }
Create a popup for the annotation's HTML element. This is used for
annotations that do not have a Popup entry in the dictionary, but
are of a type that works with popups (such as Highlight annotations).

@private
@memberof AnnotationElement