fix error message

src/test/compile-fail/rfc1445/match-forbidden-without-eq.rs

@@ -24,7 +24,7 @@ fn main() {
     let y = Foo { x: 1 };
     match y {
         FOO => { }
-        //~^ ERROR must be annotated with `#[derive(Eq)]`
+        //~^ ERROR must be annotated with `#[derive(PartialEq, Eq)]`
         //~| WARNING will become a hard error
         _ => { }
     }