Rollup merge of #92981 - RalfJung:const_ptr_offset_from, r=dtolnay

fix const_ptr_offset_from tracking issue

The old tracking issue #41079 was for exposing those functions at all, and got closed when they were stabilized. We had nothing tracking their `const`ness so I opened a new tracking issue: #92980.

Author: matthiaskrgr

library/core/src/intrinsics.rs

@@ -1893,7 +1893,7 @@ extern "rust-intrinsic" {
     pub fn nontemporal_store<T>(ptr: *mut T, val: T);
 
     /// See documentation of `<*const T>::offset_from` for details.
-    #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")]
+    #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "92980")]
     pub fn ptr_offset_from<T>(ptr: *const T, base: *const T) -> isize;
 
     /// See documentation of `<*const T>::guaranteed_eq` for details.

library/core/src/ptr/const_ptr.rs

@@ -439,7 +439,7 @@ impl<T: ?Sized> *const T {
     /// }
     /// ```
     #[stable(feature = "ptr_offset_from", since = "1.47.0")]
-    #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")]
+    #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "92980")]
     #[inline]
     pub const unsafe fn offset_from(self, origin: *const T) -> isize
     where

library/core/src/ptr/mut_ptr.rs

@@ -617,7 +617,7 @@ impl<T: ?Sized> *mut T {
     /// }
     /// ```
     #[stable(feature = "ptr_offset_from", since = "1.47.0")]
-    #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "41079")]
+    #[rustc_const_unstable(feature = "const_ptr_offset_from", issue = "92980")]
     #[inline(always)]
     pub const unsafe fn offset_from(self, origin: *const T) -> isize
     where