Update tests

tests/ui/eta.stderr

@@ -22,7 +22,7 @@ error: this expression borrows a reference that is immediately dereferenced by t
   --> $DIR/eta.rs:11:21
    |
 11 |     all(&[1, 2, 3], &&2, |x, y| below(x, y)); //is adjusted
-   |                     ^^^
+   |                     ^^^ help: change this to: `&2`
    |
    = note: `-D needless-borrow` implied by `-D warnings`
 

tests/ui/needless_borrow.stderr

@@ -2,7 +2,7 @@ error: this expression borrows a reference that is immediately dereferenced by t
   --> $DIR/needless_borrow.rs:13:15
    |
 13 |     let c = x(&&a);
-   |               ^^^
+   |               ^^^ help: change this to: `&a`
    |
    = note: `-D needless-borrow` implied by `-D warnings`
 
@@ -10,13 +10,13 @@ error: this pattern creates a reference to a reference
   --> $DIR/needless_borrow.rs:20:17
    |
 20 |     if let Some(ref cake) = Some(&5) {}
-   |                 ^^^^^^^^
+   |                 ^^^^^^^^ help: change this to: `cake`
 
 error: this expression borrows a reference that is immediately dereferenced by the compiler
   --> $DIR/needless_borrow.rs:27:15
    |
 27 |         46 => &&a,
-   |               ^^^
+   |               ^^^ help: change this to: `&a`
 
 error: this pattern takes a reference on something that is being de-referenced
   --> $DIR/needless_borrow.rs:49:34
@@ -36,7 +36,7 @@ error: this pattern creates a reference to a reference
   --> $DIR/needless_borrow.rs:50:31
    |
 50 |     let _ = v.iter().filter(|&ref a| a.is_empty());
-   |                               ^^^^^
+   |                               ^^^^^ help: change this to: `a`
 
 error: aborting due to 6 previous errors