Stabilize slice_ptr_range.

Closes #65807.

Author: m-ou-se

library/core/src/slice/mod.rs

@@ -458,8 +458,6 @@ impl<T> [T] {
     /// element of this slice:
     ///
     /// ```
-    /// #![feature(slice_ptr_range)]
-    ///
     /// let a = [1, 2, 3];
     /// let x = &a[1] as *const _;
     /// let y = &5 as *const _;
@@ -469,7 +467,7 @@ impl<T> [T] {
     /// ```
     ///
     /// [`as_ptr`]: #method.as_ptr
-    #[unstable(feature = "slice_ptr_range", issue = "65807")]
+    #[stable(feature = "slice_ptr_range", since = "1.48.0")]
     #[rustc_const_unstable(feature = "const_ptr_offset", issue = "71499")]
     #[inline]
     pub const fn as_ptr_range(&self) -> Range<*const T> {
@@ -511,7 +509,7 @@ impl<T> [T] {
     /// common in C++.
     ///
     /// [`as_mut_ptr`]: #method.as_mut_ptr
-    #[unstable(feature = "slice_ptr_range", issue = "65807")]
+    #[stable(feature = "slice_ptr_range", since = "1.48.0")]
     #[rustc_const_unstable(feature = "const_ptr_offset", issue = "71499")]
     #[inline]
     pub const fn as_mut_ptr_range(&mut self) -> Range<*mut T> {