Tweak removed feature error

Author: estebank

src/libsyntax/feature_gate/check.rs

@@ -688,10 +688,9 @@ pub fn get_features(span_handler: &Handler, krate_attrs: &[ast::Attribute],
                     crate_edition: Edition, allow_features: &Option<Vec<String>>) -> Features {
     fn feature_removed(span_handler: &Handler, span: Span, reason: Option<&str>) {
         let mut err = struct_span_err!(span_handler, span, E0557, "feature has been removed");
+        err.span_label(span, "feature has been removed");
         if let Some(reason) = reason {
-            err.span_note(span, reason);
-        } else {
-            err.span_label(span, "feature has been removed");
+            err.note(reason);
         }
         err.emit();
     }

src/test/ui/macros/macro-reexport-removed.stderr

@@ -2,13 +2,9 @@ error[E0557]: feature has been removed
   --> $DIR/macro-reexport-removed.rs:3:12
    |
 LL | #![feature(macro_reexport)]
-   |            ^^^^^^^^^^^^^^
+   |            ^^^^^^^^^^^^^^ feature has been removed
    |
-note: subsumed by `pub use`
-  --> $DIR/macro-reexport-removed.rs:3:12
-   |
-LL | #![feature(macro_reexport)]
-   |            ^^^^^^^^^^^^^^
+   = note: subsumed by `pub use`
 
 error: cannot find attribute `macro_reexport` in this scope
   --> $DIR/macro-reexport-removed.rs:5:3