Assign its own tracking issue to Box::into_raw_non_null

https://github.com/rust-lang/rust/issues/47336

src/liballoc/boxed.rs

@@ -317,12 +317,14 @@ impl<T: ?Sized> Box<T> {
     /// # Examples
     ///
     /// ```
+    /// #![feature(box_into_raw_non_null)]
+    ///
     /// fn main() {
     ///     let x = Box::new(5);
     ///     let ptr = Box::into_raw_non_null(x);
     /// }
     /// ```
-    #[unstable(feature = "nonnull", issue = "27730")]
+    #[unstable(feature = "box_into_raw_non_null", issue = "47336")]
     #[inline]
     pub fn into_raw_non_null(b: Box<T>) -> NonNull<T> {
         Box::into_unique(b).into()

src/liballoc/lib.rs

@@ -84,6 +84,7 @@
 #![cfg_attr(test, feature(rand, test))]
 #![feature(allow_internal_unstable)]
 #![feature(ascii_ctype)]
+#![feature(box_into_raw_non_null)]
 #![feature(box_patterns)]
 #![feature(box_syntax)]
 #![feature(cfg_target_has_atomic)]