Add unresolved question for leaking.

Author: boats

text/0000-pin.md

@@ -396,4 +396,8 @@ In addition to the future extensions discussed above, the APIs of the three pin
 types in std will grow over time as they implement more common conversion
 traits and so on.
 
-[stable-deref]: https://crates.io/crates/stable_deref_trait
+We may also choose to require that `Pin` uphold stricter guarantees, requiring
+that `Unpin` data inside the `Pin` not leak unless the memory remains valid for
+the remainder of the program lifetime. This would make the stack API documented
+above unsound, but might also enable other APIs to make use of these guarantees
+to ensure that a destructor always runs if the memory becomes invalid.