Update content/en/docs/concepts/storage/storage-capacity.md

Co-authored-by: Tim Bannister <tim@scalefactory.com>

content/en/docs/concepts/storage/storage-capacity.md

@@ -106,7 +106,7 @@ to handle this automatically.
 Storage capacity tracking is an *alpha feature* and only enabled when
 the `CSIStorageCapacity` [feature
 gate](/docs/reference/command-line-tools-reference/feature-gates/) and
-the `storage.k8s.io/v1alpha1` API group are enabled. For details on
+the `storage.k8s.io/v1alpha1` {{< glossary_tooltip text="API group" term_id="api-group" >}} are enabled. For details on
 that, see the `--feature-gates` and `--runtime-config` [kube-apiserver
 parameters](/docs/reference/command-line-tools-reference/kube-apiserver/).