fix: Remove a redundant <never-to-any> from adjustment hints for let-else

[WaffleLapkin]

Before:

After:

I'm not sure why an adjustment is there at all, given that else block in let-else must always evaluate to !, but we can suppress it I guess...

Continuation of #13749

[Veykril]

We seem to emit a never to never coercion there

[Veykril]

So ye this is most likely a never to never coercion as can be seen here

Now, the question is whether this coercion makes sense? (Though I assume rust also does it, in which case we should keep it)
The proper fix I think would be to probably reveal the types in the adjustment HIR api (I was lazy and figured I wouldn't need them for now which is why they are currently missing from the HIR api) and then check if this is a never to never coercion.

[WaffleLapkin]

Having types in the tooltips can be interesting too 👀

[Veykril]

Certainly, the hover messages have a lot of room for imrpovements. fwiw adding types to the API is only a matter of transforming the hir_ty::Ty into a hir::Type and exposing them iwth the adjustment kinds.

[bors]

☔ The latest upstream changes (presumably #13804) made this pull request unmergeable. Please resolve the merge conflicts.