code: function isVisiblePoint(point) {
    if (isText(point.node) || !hasChildren(point.node) || isEmpty(point.node)) {
      return true;
    }
  
    const leftNode = point.node.childNodes[point.offset - 1];
    const rightNode = point.node.childNodes[point.offset];
    if ((!leftNode || isVoid(leftNode)) && (!rightNode || isVoid(rightNode))) {
      return true;
    }
  
    return false;
  }
docs: returns whether point is visible (can set cursor) or not.
  
  @param {BoundaryPoint} point
  @return {Boolean}