Fix docs/tasks page TOC (#8999)

This pages did not use any template and the displayed toc started
with two bullet points. Use the concept template.

content/en/docs/tasks/_index.md

@@ -2,12 +2,21 @@
 title: Tasks
 main_menu: true
 weight: 50
+content_template: templates/concept
 ---
 
+{{< toc >}}
+
+{{% capture overview %}}
+
 This section of the Kubernetes documentation contains pages that
 show how to do individual tasks. A task page shows how to do a
 single thing, typically by giving a short sequence of steps.
 
+{{% /capture %}}
+
+{{% capture body %}}
+
 ## Web UI (Dashboard)
 
 Deploy and access the Dashboard web user interface to help you manage and monitor containerized applications in a Kubernetes cluster.
@@ -68,7 +77,11 @@ Configure and schedule NVIDIA GPUs for use as a resource by nodes in a cluster.
 
 Configure and schedule huge pages as a schedulable resource in a cluster.
 
-## What's next
+{{% /capture %}}
+
+{{% capture whatsnext %}}
 
 If you would like to write a task page, see
 [Creating a Documentation Pull Request](/docs/home/contribute/create-pull-request/).
+
+{{% /capture %}}