Place compile-fail expected errors on their own line

test_suite/tests/compile-fail/remote/nonremote_getter.rs

@@ -9,9 +9,10 @@
 #[macro_use]
 extern crate serde_derive;
 
-#[derive(Serialize)] //~ ERROR: 12:10: 12:19: #[serde(getter = "...")] can only be used in structs that have #[serde(remote = "...")]
+#[derive(Serialize)]
 struct S {
     #[serde(getter = "S::get")]
+    //~^^^ ERROR: #[serde(getter = "...")] can only be used in structs that have #[serde(remote = "...")]
     a: u8,
 }