Allow nested functions to refer to type parameters of the outer function

[mark-koch]

@guppy
def main[T]() -> None:
    def bar() -> None:
        x: Option[T] = nothing()

This should also fix #1036.

To do this, the inner function should inherit all type params of the outer function. Then we immediately type-apply the bound variables of the outer function

[doug-q]

• This is very hard, that's why we didn't do it
• We don't have nested functions anymore

[mark-koch]

I'm not suggesting any change to Hugr, this should be a pure frontend feature