Do not include const_ptr_sub_ptr in this stabilization

Author: fee1-dead

core/src/intrinsics.rs

@@ -2017,7 +2017,7 @@ extern "rust-intrinsic" {
     pub fn ptr_offset_from<T>(ptr: *const T, base: *const T) -> isize;
 
     /// See documentation of `<*const T>::sub_ptr` for details.
-    #[rustc_const_stable(feature = "const_ptr_offset_from", since = "1.65.0")]
+    #[rustc_const_unstable(feature = "const_ptr_sub_ptr", issue = "95892")]
     pub fn ptr_offset_from_unsigned<T>(ptr: *const T, base: *const T) -> usize;
 
     /// See documentation of `<*const T>::guaranteed_eq` for details.