Fixed alphabetical ordering of feature gate, added same to doctest

Author: madhav-madhusoodanan

library/core/src/lib.rs

@@ -116,6 +116,7 @@
 #![feature(closure_track_caller)]
 #![feature(const_carrying_mul_add)]
 #![feature(const_eval_select)]
+#![feature(control_flow_into_value)]
 #![feature(core_intrinsics)]
 #![feature(coverage_attribute)]
 #![feature(disjoint_bitor)]
@@ -141,7 +142,6 @@
 #![feature(unchecked_shifts)]
 #![feature(utf16_extra)]
 #![feature(variant_count)]
-#![feature(control_flow_into_value)]
 // tidy-alphabetical-end
 //
 // Language features:

library/core/src/ops/control_flow.rs

@@ -235,6 +235,7 @@ impl<T> ControlFlow<T, T> {
     /// # Examples
     ///
     /// ```
+    /// #![feature(control_flow_into_value)]
     /// use std::ops::ControlFlow;
     ///
     /// assert_eq!(ControlFlow::<i32, i32>::Break(1024).into_value(), 1024);