Use NOTE instead of error-pattern directive

Author: tmandry

src/test/compile-fail/rfc-1937-termination-trait/termination-trait-main-i32.rs

@@ -8,7 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:`main` can only return types like `()` that implement std::process::Termination, no
 fn main() -> i32 {
+//~^ ERROR `i32: std::process::Termination` is not satisfied
+//~| NOTE `main` can only return types like `()` that implement std::process::Termination, not `i32`
     0
 }