Merge pull request #29228 from sftim/20210804_update_apiservice_link_to_api_reference

Link to new API reference page for APIService

Author: k8s-ci-robot

content/en/docs/concepts/extend-kubernetes/api-extension/apiserver-aggregation.md

@@ -34,7 +34,7 @@ If your extension API server cannot achieve that latency requirement, consider m
 
 * To get the aggregator working in your environment, [configure the aggregation layer](/docs/tasks/extend-kubernetes/configure-aggregation-layer/).
 * Then, [setup an extension api-server](/docs/tasks/extend-kubernetes/setup-extension-api-server/) to work with the aggregation layer.
-* Also, learn how to [extend the Kubernetes API using Custom Resource Definitions](/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/).
-* Read the specification for [APIService](/docs/reference/generated/kubernetes-api/{{< param "version" >}}/#apiservice-v1-apiregistration-k8s-io)
+* Read about [APIService](/docs/reference/kubernetes-api/cluster-resources/api-service-v1/) in the API reference
 
+Alternatively: learn how to [extend the Kubernetes API using Custom Resource Definitions](/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/).