Correct error location indicated by comments

Author: kleimkuhler

Diff for: src/test/ui/feature-gates/feature-gate-is_sorted.rs

@@ -1,13 +1,13 @@
 fn main() {
     // Assert `Iterator` methods are feature gated
     assert!([1, 2, 2, 9].iter().is_sorted());
-    //^ ERROR: use of unstable library feature 'is_sorted'
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
     assert!(![-2i32, -1, 0, 3].iter().is_sorted_by_key(|n| n.abs()));
-    //^ ERROR: use of unstable library feature 'is_sorted'
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
 
     // Assert `[T]` methods are feature gated
     assert!([1, 2, 2, 9].is_sorted());
-    //^ ERROR: use of unstable library feature 'is_sorted'
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
     assert!(![-2i32, -1, 0, 3].is_sorted_by_key(|n| n.abs()));
-    //^ ERROR: use of unstable library feature 'is_sorted'
+    //~^ ERROR: use of unstable library feature 'is_sorted': new API
 }