Update stabilization version of impl Not for !

Author: dtolnay

library/core/src/ops/bit.rs

@@ -68,7 +68,7 @@ macro_rules! not_impl {
 
 not_impl! { bool usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
 
-#[stable(feature = "not_never", since = "1.58.0")]
+#[stable(feature = "not_never", since = "1.60.0")]
 #[rustc_const_unstable(feature = "const_ops", issue = "90080")]
 impl const Not for ! {
     type Output = !;