Update TOC and change "overview" to "index"

This changes the index page URL for cluster to `/cluster/`
instead of `/cluster/overview/`, which makes URL navigation
more fitting the expectations.

Note that there's still issues to resolve; because we're adding links
to the *same* "reference" pages and "environment variables" in multiple
locations in the navigation tree, the navigation marks all occurrences
as "active". Which means that browsing the Docker CLI reference, and
going to the "cluster" section, will make the navigation jump to the
"Deploy Docker Enterprise" section.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

_data/toc.yaml

@@ -1308,7 +1308,7 @@ manuals:
       nosync: true
   - sectiontitle: Docker Cluster
     section:
-    - path: /cluster/overview/
+    - path: /cluster/
       title: Overview
     - path: /cluster/aws/
       title: Docker Cluster on AWS

cluster/aws.md

@@ -399,4 +399,4 @@ All provisioned resources are destroyed and the context for the cluster is remov
 
 - View the quick start guide for [Azure](azure.md) or [vSphere](vsphere.md)
 - [Explore the full list of Cluster commands](/engine/reference/commandline/cluster/)
-- [Cluster configuration file reference](./cluster-file/index.md)
+- [Cluster configuration file reference](./cluster-file.md)

cluster/index.md

@@ -46,7 +46,7 @@ resource:
 {% endraw %}
 
 For more information about Cluster files, refer to the
-[Cluster file reference](cluster-file/index.md).
+[Cluster file reference](cluster-file.md).
 
 Docker Cluster has commands for managing the whole lifecycle of your cluster:
 
@@ -60,5 +60,5 @@ Docker Cluster has commands for managing the whole lifecycle of your cluster:
 
 - [Get started with Docker Cluster on AWS](aws.md)
 - [Command line reference](/engine/reference/commandline/cluster/)
-- [Cluster file reference](./cluster-file/index.md)
+- [Cluster file reference](./cluster-file.md)
 

ee/release-notes.md

@@ -20,7 +20,7 @@ keywords: engine enterprise, ucp, dtr, desktop enterprise, whats new, release no
 | [Docker App (Experimental)](/app/working-with-app/) |CLI | 0.8.0 |
 | [Docker Assemble (Experimental)](/assemble/install/) | CLI | 0.36.0 |
 | [Docker Buildx (Experimental)](/buildx/working-with-buildx/)| CLI | 0.2.2 |
-| [Docker Cluster](/cluster/overview/) | CLI | 1.0.0 |
+| [Docker Cluster](/cluster/) | CLI | 1.0.0 |
 | [Docker Template CLI (Experimental)](/app-template/working-with-template/) | CLI | 0.1.4 |