Rollup merge of rust-lang#115605 - ouz-a:smir_better_debug, r=oli-obk

Better Debug for `Ty` in smir

Similar to what I did here rust-lang#115534.

r? ``@oli-obk``

compiler/rustc_smir/src/stable_mir/ty.rs

@@ -4,10 +4,17 @@ use super::{
     with, AllocId, DefId,
 };
 use crate::rustc_internal::Opaque;
+use std::fmt::{self, Debug, Formatter};
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone)]
 pub struct Ty(pub usize);
 
+impl Debug for Ty {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.debug_struct("Ty").field("id", &self.0).field("kind", &self.kind()).finish()
+    }
+}
+
 impl Ty {
     pub fn kind(&self) -> TyKind {
         with(|context| context.ty_kind(*self))