Issue #3455110 by jagraj_singh_gill, joachim: HandlerStackConfigurator has...

Issue #3455110 by jagraj_singh_gill, joachim: HandlerStackConfigurator has @see to class that no longer exists

(cherry picked from commit e4c14cfd)

core/lib/Drupal/Core/Http/HandlerStackConfigurator.php

@@ -16,7 +16,7 @@
  *
  * @see https://guzzle.readthedocs.org/en/latest/handlers-and-middleware.html
  *
- * @see \Drupal\Core\Http\Client
+ * @see \GuzzleHttp\Client
  * @see \Drupal\Core\Test\HttpClientMiddleware\TestHttpClientMiddleware
  */
 class HandlerStackConfigurator {