Rollup merge of #99651 - compiler-errors:fn-and-raw-ptr-in-const-generics, r=oli-obk

Deeply deny fn and raw ptrs in const generics

I think this is right -- just because we wrap a fn ptr in a wrapper type does not mean we should allow it in a const parameter.

We now reject both of these in the same way:

```
#![feature(adt_const_params)]

#[derive(Eq, PartialEq)]
struct Wrapper();

fn foo<const W: Wrapper>() {}

fn foo2<const F: fn()>() {}
```

This does regress one test (`src/test/ui/consts/refs_check_const_eq-issue-88384.stderr`), but I'm not sure it should've passed in the first place.

cc: ``@b-naber`` who introduced that test^
fixes #99641

compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs

@@ -226,7 +226,7 @@ impl Qualif for CustomEq {
         // because that component may be part of an enum variant (e.g.,
         // `Option::<NonStructuralMatchTy>::Some`), in which case some values of this type may be
         // structural-match (`Option::None`).
-        traits::search_for_structural_match_violation(cx.body.span, cx.tcx, ty, true).is_some()
+        traits::search_for_structural_match_violation(cx.body.span, cx.tcx, ty).is_some()
     }
 
     fn in_adt_inherently<'tcx>(