Admit that some objects don't have a spec (#18050)

Whilst most objects have a spec, it will confuse readers who come to
this page from a page about an object that doesn't (eg Secret,
Namespace, Role).

Author: Tim Bannister

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

@@ -26,10 +26,27 @@ To work with Kubernetes objects--whether to create, modify, or delete them--you'
 
 ### Object Spec and Status
 
-Every Kubernetes object includes two nested object fields that govern the object's configuration: the object *spec* and the object *status*. The *spec*, which you must provide, describes your desired state for the object--the characteristics that you want the object to have. The *status* describes the *actual state* of the object, and is supplied and updated by the Kubernetes system. At any given time, the Kubernetes Control Plane actively manages an object's actual state to match the desired state you supplied.
-
-
-For example, a Kubernetes Deployment is an object that can represent an application running on your cluster. When you create the Deployment, you might set the Deployment spec to specify that you want three replicas of the application to be running. The Kubernetes system reads the Deployment spec and starts three instances of your desired application--updating the status to match your spec. If any of those instances should fail (a status change), the Kubernetes system responds to the difference between spec and status by making a correction--in this case, starting a replacement instance.
+Almost every Kubernetes object includes two nested object fields that govern
+the object's configuration: the object *`spec`* and the object *`status`*.
+For objects that have a `spec`, you have to set this when you create the object,
+providing a description of the characteristics you want the resource to have:
+its _desired state_.
+
+The `status` describes the _current state_ of the object, supplied and updated
+by the Kubernetes and its components. The Kubernetes
+{{< glossary_tooltip text="control plane" term_id="control-plane" >}} continually
+and actively manages every object's actual state to match the desired state you
+supplied.
+
+For example: in Kubernetes, a Deployment is an object that can represent an
+application running on your cluster. When you create the Deployment, you
+might set the Deployment `spec` to specify that you want three replicas of
+the application to be running. The Kubernetes system reads the Deployment
+spec and starts three instances of your desired application--updating
+the status to match your spec. If any of those instances should fail
+(a status change), the Kubernetes system responds to the difference
+between spec and status by making a correction--in this case, starting
+a replacement instance.
 
 For more information on the object spec, status, and metadata, see the [Kubernetes API Conventions](https://git.k8s.io/community/contributors/devel/sig-architecture/api-conventions.md).