[CI:DOCS] Image tree endpoint should return 404
when trying to get an image tree for a missing image, it should return a 404.  doc fix only.
Fixes:
@@ -698,7 +698,7 @@ func (s *APIServer) registerImagesHandlers(r *mux.Router) error {
// responses:
// 200:
// $ref: '#/responses/LibpodImageTreeResponse'
- // 401:
+ // 404:
// $ref: '#/responses/NoSuchImage'
// 500:
// $ref: '#/responses/InternalError'
