Bring shim.rs up-to-date

Author: nbdd0121

src/mir/drop_shim.rs

@@ -146,8 +146,8 @@ pub struct DropShimElaborator<'a, 'tcx> {
 }
 
 impl fmt::Debug for DropShimElaborator<'_, '_> {
-    fn fmt(&self, _f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
-        Ok(())
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
+        f.debug_struct("DropShimElaborator").finish_non_exhaustive()
     }
 }