Attributes of `types.FunctionType` should be available on `lambda` functions

[AlexWaygood]

Summary

ty currently emits a false-positive diagnostic on this snippet:

from typing import reveal_type

x = lambda y: y

# error[unresolved-attribute] Type `(y) -> Unknown` has no attribute `__code__`
reveal_type(x.__code__)  # revealed: Unknown

https://play.ty.dev/84a1b067-9670-4463-82ce-0fc025997c91

All lambda functions are instances of types.FunctionType, so all attributes available on types.FunctionType instances should also be available on lambdas.

Following astral-sh/ruff#18242 this is easy to fix: we just need to change this line so that it calls CallableType::function_like() rather than CallableType::single() (and add some tests).

[lipefree]

I can try to resolve this issue !