Update ui test expectations

Author: alexcrichton

crates/macro/ui-tests/pub-not-copy.stderr

@@ -2,10 +2,11 @@ error[E0277]: the trait bound `std::string::String: std::marker::Copy` is not sa
  --> $DIR/pub-not-copy.rs:5:16
   |
 3 | #[wasm_bindgen]
-  | --------------- required by `__wbg_get_a_field::assert_copy`
+  | ---------------
+  | |
+  | required by this bound in `__wbg_get_a_field::assert_copy`
 4 | pub struct A {
 5 |     pub field: String,
   |                ^^^^^^ the trait `std::marker::Copy` is not implemented for `std::string::String`
 
 For more information about this error, try `rustc --explain E0277`.
-error: could not compile `wasm-bindgen-macro-tests`.