code: func TokenField(c context.Context) template.HTML {
  	tok, err := Token(c)
  	if err != nil {
  		panic(err)
  	}
  	return template.HTML(fmt.Sprintf(`<input type="hidden" name="xsrf_token" value="%s">`, html.EscapeString(tok)))
  }
docs: // TokenField generates "<input type="hidden" ...>" field with the token.
  //
  // It can be put into HTML forms directly. Panics on errors.