Clarify "external registry" is actually "third-party"

doc/administration/packages/container_registry.md

@@ -838,9 +838,9 @@ project, you can [disable it from your project's settings](../../user/project/se
 ## Use an external container registry with GitLab as an auth endpoint
 
 WARNING:
-Using external container registries in GitLab is [deprecated](https://gitlab.com/gitlab-org/gitlab/-/issues/376217)
-in GitLab 15.8 and the end of support is scheduled for GitLab 16.0.
-If you need to use external container registries instead of the GitLab container registry,
+Using third-party container registries in GitLab was [deprecated](https://gitlab.com/gitlab-org/gitlab/-/issues/376217)
+in GitLab 15.8 and support ended in GitLab 16.0.
+If you need to use third-party container registries instead of the GitLab container registry,
 tell us about your use cases in [feedback issue 958](https://gitlab.com/gitlab-org/container-registry/-/issues/958).
 
 If you use an external container registry, some features associated with the