Add iter_at_least and iter_at_most feature flags

Author: Folyd

library/core/src/iter/traits/iterator.rs

@@ -2310,7 +2310,7 @@ pub trait Iterator {
     /// assert_eq!(iter.next(), Some(&2));
     /// ```
     #[inline]
-    #[unstable(feature = "at_least", reason = "new API", issue = "none")]
+    #[unstable(feature = "iter_at_least", reason = "new API", issue = "none")]
     fn at_least<F>(&mut self, n: usize, f: F) -> bool
         where
             Self: Sized,
@@ -2379,7 +2379,7 @@ pub trait Iterator {
     /// assert_eq!(iter.next(), Some(&3));
     /// ```
     #[inline]
-    #[unstable(feature = "at_most", reason = "new API", issue = "none")]
+    #[unstable(feature = "iter_at_most", reason = "new API", issue = "none")]
     fn at_most<F>(&mut self, n: usize, f: F) -> bool
         where
             Self: Sized,

library/core/tests/lib.rs

@@ -77,6 +77,8 @@
 #![feature(integer_atomics)]
 #![feature(slice_group_by)]
 #![feature(trusted_random_access)]
+#![feature(iter_at_least)]
+#![feature(iter_at_most)]
 #![deny(unsafe_op_in_unsafe_fn)]
 
 extern crate test;