code: func pathSuffix(path string) string {
  	const pathSep = "/"
  	lastSep := strings.LastIndex(path, pathSep)
  	if lastSep == -1 {
  		return path
  	}
  	return path[strings.LastIndex(path[:lastSep], pathSep)+1:]
  }
docs: // pathSuffix returns the last two segments of path.