Fix incorrect usages of rustc_const_stable attribute.

Author: tobz

library/core/src/ptr/mod.rs

@@ -255,7 +255,7 @@ pub const fn null_mut<T>() -> *mut T {
 /// ```
 #[inline]
 #[stable(feature = "slice_from_raw_parts", since = "1.42.0")]
-#[rustc_const_stable(since = "1.61.0")]
+#[rustc_const_stable(feature = "const_slice_from_raw_parts", since = "1.61.0")]
 pub const fn slice_from_raw_parts<T>(data: *const T, len: usize) -> *const [T] {
     from_raw_parts(data.cast(), len)
 }

library/core/src/slice/raw.rs

@@ -84,7 +84,7 @@ use crate::ptr;
 /// [`NonNull::dangling()`]: ptr::NonNull::dangling
 #[inline]
 #[stable(feature = "rust1", since = "1.0.0")]
-#[rustc_const_stable(since = "1.61.0")]
+#[rustc_const_stable(feature = "const_slice_from_raw_parts", since = "1.61.0")]
 pub const unsafe fn from_raw_parts<'a, T>(data: *const T, len: usize) -> &'a [T] {
     debug_check_data_len(data, len);