Update ui test output

Author: GuillaumeGomez

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

@@ -30,4 +30,5 @@ LL | fn projection_is_disallowed(x: impl Iterator) -> <impl Iterator>::Item {
 
 error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0223`.
+Some errors have detailed explanations: E0223, E0667.
+For more information about an error, try `rustc --explain E0223`.

src/test/ui/impl-trait/issues/issue-57979-impl-trait-in-path.stderr

@@ -6,3 +6,4 @@ LL | pub fn demo(_: impl Quux<(), Assoc=<() as Quux<impl Bar>>::Assoc>) { }
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0667`.