Rollup merge of rust-lang#144900 - Kivooeo:unsigned_signed_diff-stabilize, r=dtolnay

Stabilize `unsigned_signed_diff` feature

This closes [tracking issue](rust-lang#126041) and stabilises `checked_signed_diff`

r? libs-api

Author: samueltardieu

library/core/src/num/uint_macros.rs

@@ -844,7 +844,6 @@ macro_rules! uint_impl {
         /// # Examples
         ///
         /// ```
-        /// #![feature(unsigned_signed_diff)]
         #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")]
         #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")]
         #[doc = concat!(
@@ -882,7 +881,8 @@ macro_rules! uint_impl {
             "::MAX), Some(0));"
         )]
         /// ```
-        #[unstable(feature = "unsigned_signed_diff", issue = "126041")]
+        #[stable(feature = "unsigned_signed_diff", since = "CURRENT_RUSTC_VERSION")]
+        #[rustc_const_stable(feature = "unsigned_signed_diff", since = "CURRENT_RUSTC_VERSION")]
         #[inline]
         pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> {
             let res = self.wrapping_sub(rhs) as $SignedT;

library/std/src/lib.rs

@@ -321,7 +321,6 @@
 #![feature(try_blocks)]
 #![feature(try_trait_v2)]
 #![feature(type_alias_impl_trait)]
-#![feature(unsigned_signed_diff)]
 // tidy-alphabetical-end
 //
 // Library features (core):