code: func (s *GeoDistanceSort) DistanceType(distanceType string) *GeoDistanceSort {
  	s.distanceType = &distanceType
  	return s
  }
docs: // DistanceType describes how to compute the distance, e.g. "arc" or "plane".
  // See https://www.elastic.co/guide/en/elasticsearch/reference/7.0/search-request-sort.html#geo-sorting
  // for details.