Fix e0658 ui test

Author: mark-i-m

src/test/ui/error-codes/E0658.rs

@@ -8,6 +8,9 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-fn main() {
-    let _ = ::std::u128::MAX; //~ ERROR E0658
+#[repr(u128)]
+enum Foo { //~ ERROR E0658
+    Bar(u64),
 }
+
+fn main() {}

src/test/ui/error-codes/E0658.stderr

@@ -1,10 +1,12 @@
-error[E0658]: use of unstable library feature 'i128' (see issue #35118)
-  --> $DIR/E0658.rs:12:13
+error[E0658]: repr with 128-bit type is unstable (see issue #35118)
+  --> $DIR/E0658.rs:12:1
    |
-LL |     let _ = ::std::u128::MAX; //~ ERROR E0658
-   |             ^^^^^^^^^^^^^^^^
+LL | / enum Foo { //~ ERROR E0658
+LL | |     Bar(u64),
+LL | | }
+   | |_^
    |
-   = help: add #![feature(repri128)] to the crate attributes to enable
+   = help: add #![feature(repr128)] to the crate attributes to enable
 
 error: aborting due to previous error