ruff

ef1802b9 - [ty] Repurpose `FunctionType.into_bound_method_type` to return `BoundMethodType` (#19793)

[ty] Repurpose `FunctionType.into_bound_method_type` to return `BoundMethodType` (#19793) ## Summary As per our naming scheme (at least for callable types) this should return a `BoundMethodType`, or be renamed, but it makes more sense to change the return type. I also ensure `ClassType.into_callable` returns a `Type::Callable` in the changed branch. Ideally we could return a `CallableType` from these `into_callable` functions (and rename to `into_callable_type` but because of unions we cannot do this.