implement review comment

Co-authored-by: Esteban Kuber <estebank@users.noreply.github.com>

Author: Ezrashaw

compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs

@@ -1268,9 +1268,9 @@ fn suggest_ampmut<'tcx>(
         // shrink the span to just after the `&` in `&variable`
         let span = span.with_lo(span.lo() + BytePos(1)).shrink_to_lo();
         (true, span, "mut ".to_owned())
-    // otherwise, suggest that the user annotates the binding; we provide the
-    // type of the local.
     } else {
+        // otherwise, suggest that the user annotates the binding; we provide the
+        // type of the local.
         let ty_mut = local_decl.ty.builtin_deref(true).unwrap();
         assert_eq!(ty_mut.mutbl, hir::Mutability::Not);