Fix test

Author: estebank

src/test/ui/suggestions/dont-suggest-dereference-on-arg.rs

@@ -14,5 +14,8 @@ fn main() {
     let x = vec![(String::new(), String::new())];
     x.iter()
         .filter(|&(ref a, _)| foo(a))
+        //~^ ERROR non-reference pattern used to match a reference
+        //~| HELP consider using a reference
+        //~| HELP add
         .collect();
 }

src/test/ui/suggestions/dont-suggest-dereference-on-arg.stderr

@@ -1,8 +1,8 @@
 error: non-reference pattern used to match a reference (see issue #42640)
-  --> $DIR/dont-suggest-dereference-on-arg.rs:16:19
+  --> $DIR/dont-suggest-dereference-on-arg.rs:16:18
    |
 16 |         .filter(|&(ref a, _)| foo(a))
-   |                  ^^^^^^^^^^^ help: consider using a reference: `&&(ref k, _)`
+   |                  ^^^^^^^^^^^ help: consider using a reference: `&&(ref a, _)`
    |
    = help: add #![feature(match_default_bindings)] to the crate attributes to enable