Make KeyComboAction.get_model_action more concise
Make KeyComboAction.get_model_action more concise

Since cursor_info and is_mac are only used in a small number of cases, they are best handled by adding when conditions to the patters.

Also, Some(EditAction(Construct))) was a really common pattern to be returned, so it could be abstracted to a simple function.

hazelgrove/hazel,hazelgrove/hazel,hazelgrove/hazel