Move span in error (fixup rust-lang#22764)

Author: Manishearth

src/test/compile-fail/issue-16747.rs

@@ -18,11 +18,10 @@ trait Collection { fn len(&self) -> usize; }
 
 struct List<'a, T: ListItem<'a>> {
 //~^ ERROR the parameter type `T` may not live long enough
-//~^^ HELP consider adding an explicit lifetime bound
-//~^^^ NOTE ...so that the reference type `&'a [T]` does not outlive the data it points at
+//~^^ NOTE ...so that the reference type `&'a [T]` does not outlive the data it points at
     slice: &'a [T]
 }
-
+//~^ HELP consider adding an explicit lifetime bound
 impl<'a, T: ListItem<'a>> Collection for List<'a, T> {
     fn len(&self) -> usize {
         0