Adjust documentation for slice_check_range

Author: dylni

library/core/src/slice/mod.rs

@@ -399,7 +399,7 @@ impl<T> [T] {
     ///
     /// [`Index::index`]: ops::Index::index
     #[track_caller]
-    #[unstable(feature = "slice_check_range", issue = "none")]
+    #[unstable(feature = "slice_check_range", issue = "76393")]
     pub fn check_range<R: RangeBounds<usize>>(&self, range: R) -> Range<usize> {
         let start = match range.start_bound() {
             Bound::Included(&start) => start,

src/doc/unstable-book/src/library-features/slice-check-range.md

@@ -0,0 +1,10 @@
+# `slice_check_range`
+
+The tracking issue for this feature is: [#76393]
+
+------------------------
+
+This adds [`slice::check_range`].
+
+[#76393]: https://github.com/rust-lang/rust/issues/76393
+[`slice::check_range`]: https://doc.rust-lang.org/nightly/std/primitive.slice.html#method.check_range