Apply templates to all concepts and tasks to fix double bullets in TOC (#9149)

* Apply concept template to fix double bullet issue.

* Apply concept template

* Apply templates to tasks

content/en/docs/concepts/overview/working-with-objects/namespaces.md

@@ -4,12 +4,21 @@ reviewers:
 - mikedanese
 - thockin
 title: Namespaces
+content_template: templates/concept
 weight: 30
 ---
 
+{{% capture overview %}}
+
 Kubernetes supports multiple virtual clusters backed by the same physical cluster.
 These virtual clusters are called namespaces.
 
+{{% /capture %}}
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+{{< toc >}}
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 ## When to Use Multiple Namespaces
 
 Namespaces are intended for use in environments with many users spread across multiple
@@ -88,3 +97,5 @@ Most Kubernetes resources (e.g. pods, services, replication controllers, and oth
 in some namespaces.  However namespace resources are not themselves in a namespace.
 And low-level resources, such as [nodes](/docs/admin/node) and
 persistentVolumes, are not in any namespace.
+
+{{% /capture %}}