Merge branch 'clarify-kas-docs' into 'master'

Clarify between Kubernetes Agent Server and Kubernetes Agent in docs

See merge request gitlab-org/gitlab!45812

doc/user/clusters/agent/index.md

@@ -66,16 +66,16 @@ The setup process involves a few steps to enable GitOps deployments:
 1. Installing the Agent into the cluster.
 1. Creating a `manifest.yaml`.
 
-### Install the Agent server
+### Install the Kubernetes Agent Server
 
-The GitLab Kubernetes Agent can be deployed using [Omnibus
+The GitLab Kubernetes Agent Server (KAS) can be deployed using [Omnibus
 GitLab](https://docs.gitlab.com/omnibus/) or the [GitLab
 chart](https://gitlab.com/gitlab-org/charts/gitlab). If you don't already have
 GitLab installed, please refer to our [installation
 documentation](https://docs.gitlab.com/ee/install/README.html).
 
 NOTE: **Note:**
-GitLab plans to include the Agent on [GitLab.com](https://gitlab.com/groups/gitlab-org/-/epics/3834).
+GitLab plans to include the KAS on [GitLab.com](https://gitlab.com/groups/gitlab-org/-/epics/3834).
 
 When using the [Omnibus GitLab](https://docs.gitlab.com/omnibus/) package:
 
@@ -89,7 +89,7 @@ gitlab_kas['enable'] = true
 
 When installing or upgrading the GitLab Helm chart, consider the following Helm 2 example.
 (If you're using Helm 3, you must modify this example.) You must set `global.kas.enabled=true`
-for the Agent to be properly installed and configured:
+for the KAS to be properly installed and configured:
 
 ```shell
 helm repo update