Rollup merge of #110660 - compiler-errors:placeholders-pretty, r=wesleywiser,BoxyUwU

Print ty placeholders pretty

Makes anon placeholders print like `!0` instead of `Placeholder { ... }`.

```
rustc_trait_selection::solve::compute_well_formed_goal goal=Goal{
    predicate: !0,
    param_env: ParamEnv{
      caller_bounds: [
        Binder(TraitPredicate(<!0 as std::marker::Copy>, polarity: Positive), []),
        Binder(TraitPredicate(<!0 as std::clone::Clone>, polarity: Positive), []),
        Binder(TraitPredicate(<!0 as std::marker::Sized>, polarity: Positive), []),
      ],
      reveal: UserFacing,
      constness: NotConst,
    }
  }
```

cc `@BoxyUwU` who might care about this formatting decision

0 files changed, 0 insertions, 0 deletions