Add “API group” to glossary #15906 (#16192)

Created API Group glossary term
Linked glossary term to applicable pages

content/en/docs/reference/access-authn-authz/authorization.md

@@ -52,7 +52,7 @@ Kubernetes reviews only the following API request attributes:
  * **Resource** - The ID or name of the resource that is being accessed (for resource requests only) -- For resource requests using `get`, `update`, `patch`, and `delete` verbs, you must provide the resource name.
  * **Subresource** - The subresource that is being accessed (for resource requests only).
  * **Namespace** - The namespace of the object that is being accessed (for namespaced resource requests only).
- * **API group** - The API group being accessed (for resource requests only). An empty string designates the [core API group](/docs/concepts/overview/kubernetes-api/).
+ * **API group** - The {{< glossary_tooltip text="API Group" term_id="api-group" >}} being accessed (for resource requests only). An empty string designates the [core API group](/docs/concepts/overview/kubernetes-api/).
 
 ## Determine the Request Verb
 

content/en/docs/reference/access-authn-authz/rbac.md

@@ -13,7 +13,7 @@ Role-based access control (RBAC) is a method of regulating access to computer or
 {{% /capture %}}
 
 {{% capture body %}}
-`RBAC` uses the `rbac.authorization.k8s.io` API group
+`RBAC` uses the `rbac.authorization.k8s.io` {{< glossary_tooltip text="API Group" term_id="api-group" >}}
 to drive authorization decisions, allowing admins to dynamically configure policies
 through the Kubernetes API.
 
@@ -286,7 +286,7 @@ rules:
 
 Only the `rules` section is shown in the following examples.
 
-Allow reading the resource "pods" in the core API group:
+Allow reading the resource "pods" in the core {{< glossary_tooltip text="API Group" term_id="api-group" >}}:
 
 ```yaml
 rules: