These aliases were used because the class has properties called
`int` and `bytes`. I think it is better to use the shadowed types
from the builtins module. This should not change anything from the
type checking side but it improves the IDE experience[^1].
[^1]: I was using uuid recently and the aliases showed up in vscode,
I thought they were uuid special types and had to look in the stub to
know what they are.
The python type system doesn't provide a way to fully express the type of
`self.NestedClass` with inheritance but this change is still an improvement
over the `Any` annotations. The usage of `_Section` is rare and subclassing
it is even rarer so this shouldn't cause trouble.
