squash: 'strictly not required' -> 'never used'

Signed-off-by: Andrew Keesler <[email protected]>

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

@@ -966,7 +966,7 @@ When run from an interactive session (i.e., a terminal), `stdin` can be exposed
 to the plugin. Plugins should use the `spec.interactive` field of the input
 `ExecCredential` object from the `KUBERNETES_EXEC_INFO` environment variable in order to
 determine if `stdin` has been provided. A plugin's `stdin` requirements (i.e., whether
-`stdin` is optional, strictly required, or strictly not required in order for the plugin
+`stdin` is optional, strictly required, or never used in order for the plugin
 to run successfully) must be declared via the `user.exec.interactiveMode` field in the
 [kubeconfig](/docs/concepts/configuration/organize-cluster-access-kubeconfig/) (see table
 below for valid values).