Éric Araujo email@example.com added the comment:
Due to implementation details and history of CPython, it is not “more correct” to say that int is a function and a class. You could argue either. The question is however moot; when you mark up something with a mod, func, class or meth role, Sphinx will find the target without paying attention to its type. So changing :func: to :class: does not bring anything.