[Typing-sig] Re: "Patterned" variadic generics

What about a `builtins.map` analogue; `TypeMap[MyGeneric, *Ts]`: def product(it: Iterable[*Ts]) -> Iterable[TypeMap[tuple, *Ts]]: ... def zip(it: Iterable[*Ts]) -> Iterable[TypeMap[tuple, *Ts]]: ... def map(f: Callable[P, S], it: TypeMap[Iterable, P]) -> Iterable[S]: ... def make_boxed(x: *Ts) -> tuple[*TypeMap[Boxed, *Ts]]: ...