code: func (s *SearchDsl) Facet(f *FacetDsl) *SearchDsl {
  	s.FacetVal = f
  	return s
  }
docs: // Facet passes a Query expression to this search
  //
  //		qry := Search("github").Size("0").Facet(
  //					Facet().Regex("repository.name", "no.*").Size("8"),
  //				)
  //
  //		qry := Search("github").Pretty().Facet(
  //					Facet().Fields("type").Size("25"),
  //				)