code: func (s *SearchService) Repositories(ctx context.Context, query string, opt *SearchOptions) (*RepositoriesSearchResult, *Response, error) {
  	result := new(RepositoriesSearchResult)
  	resp, err := s.search(ctx, "repositories", &searchParameters{Query: query}, opt, result)
  	return result, resp, err
  }
docs: // Repositories searches repositories via various criteria.
  //
  // GitHub API docs: https://developer.github.com/v3/search/#search-repositories