The documentation for rules:changes states that
rules: changes works exactly the same way as only: changes and except: changes, accepting an array of paths. Similarly, it will always return true if there is no Git push event. See only/except: changes for more information.
It then provides an example of how to do the equivalent of only: changes using rules: syntax, but it does not provide an example of how to do except: changes. What is the proper syntax for except: changes using rules:?