Fix test

Author: estebank

src/test/ui/derives/issue-97343.stderr

@@ -6,6 +6,11 @@ LL | #[derive(Debug)]
 LL | pub struct Irrelevant<Irrelevant> {
    |                       ^^^^^^^^^^ type argument not allowed
    |
+note: type parameter `Irrelevant` defined here
+  --> $DIR/issue-97343.rs:4:23
+   |
+LL | pub struct Irrelevant<Irrelevant> {
+   |                       ^^^^^^^^^^
    = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: aborting due to previous error