Suggest the [const] Destruct bound for type parameters in const functions when missing

[jakubadamw]

When a const function drops a value whose type is a type parameter without a [const] Destruct bound, suggest adding it so that the destructor can be evaluated at compile-time.

Closes #103270.

Example:

const fn f(_x: impl std::fmt::Debug) {}

Before:

error[E0493]: destructor of `impl std::fmt::Debug` cannot be evaluated at compile-time
  --> $DIR/min_const_fn.rs:1:11
   |
LL | const fn f(_x: impl std::fmt::Debug) {}
   |                  ^^                         - value is dropped here
   |                  |
   |                  the destructor for this type cannot be evaluated in constant functions

After:

error[E0493]: destructor of `impl std::fmt::Debug` cannot be evaluated at compile-time
  --> $DIR/min_const_fn.rs:1:11
   |
LL | const fn f(_x: impl std::fmt::Debug) {}
   |                  ^^                         - value is dropped here
   |                  |
   |                  the destructor for this type cannot be evaluated in constant functions
   |
help: consider restricting opaque type `impl std::fmt::Debug` with unstable trait `Destruct`
   |
LL | const fn f(_x: impl std::fmt::Debug + [const] Destruct) {}
   |                                           ++++++++++++++++++

No new tests as the existing ones had their results updated with the new suggestion.

[rustbot]

Some changes occurred to constck

cc @fee1-dead

Some changes occurred to the CTFE machinery

cc @RalfJung, @oli-obk, @lcnr

[rustbot]

r? @wesleywiser

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[Kivooeo]

thanks for the contribution, but this is experimental syntax which means syntax may change in future, so I think it should be held until stabilization