update test

src/test/ui/suggestions/issue-51244.rs

@@ -10,5 +10,5 @@
 
 fn main() {
     let ref my_ref @ _ = 0;
-    *my_ref = 0;
+    *my_ref = 0; //~ ERROR cannot assign to immutable borrowed content `*my_ref` [E0594]
 }

src/test/ui/suggestions/issue-51244.stderr

@@ -2,8 +2,8 @@ error[E0594]: cannot assign to immutable borrowed content `*my_ref`
   --> $DIR/issue-51244.rs:13:5
    |
 LL |     let ref my_ref @ _ = 0;
-   |         --- consider changing this to `ref mut`
-LL |     *my_ref = 0;
+   |         -------------- consider changing this to `ref mut my_ref @ _`
+LL |     *my_ref = 0; //~ ERROR cannot assign to immutable borrowed content `*my_ref` [E0594]
    |     ^^^^^^^^^^^ cannot borrow as mutable
 
 error: aborting due to previous error