Add/Fix stderr references for impl Trait ui tests

src/test/ui/impl-trait/universal-mismatched-type.stderr

@@ -7,7 +7,7 @@ error[E0308]: mismatched types
    |     ^ expected struct `std::string::String`, found type parameter
    |
    = note: expected type `std::string::String`
-              found type ``
+              found type `impl Debug`
 
 error: aborting due to previous error
 

src/test/ui/impl-trait/universal_wrong_bounds.stderr

@@ -0,0 +1,30 @@
+error[E0425]: cannot find function `wants_clone` in this scope
+  --> $DIR/universal_wrong_bounds.rs:18:5
+   |
+18 |     wants_clone(f);
+   |     ^^^^^^^^^^^ did you mean `wants_cone`?
+
+error[E0405]: cannot find trait `Debug` in this scope
+  --> $DIR/universal_wrong_bounds.rs:21:24
+   |
+21 | fn wants_debug(g: impl Debug) { }
+   |                        ^^^^^ not found in this scope
+   |
+help: possible candidate is found in another module, you can import it into scope
+   |
+13 | use std::fmt::Debug;
+   |
+
+error[E0405]: cannot find trait `Debug` in this scope
+  --> $DIR/universal_wrong_bounds.rs:22:26
+   |
+22 | fn wants_display(g: impl Debug) { }
+   |                          ^^^^^ not found in this scope
+   |
+help: possible candidate is found in another module, you can import it into scope
+   |
+13 | use std::fmt::Debug;
+   |
+
+error: cannot continue compilation due to previous error
+