Rollup merge of #89951 - ojeda:stable-unwrap_unchecked, r=dtolnay

Stabilize `option_result_unwrap_unchecked`

Closes https://github.com/rust-lang/rust/issues/81383.

Stabilization report: https://github.com/rust-lang/rust/issues/81383#issuecomment-944498212.

```@rustbot``` label +A-option-result +T-libs-api

library/alloc/src/lib.rs

@@ -112,7 +112,6 @@
 #![feature(maybe_uninit_slice)]
 #![cfg_attr(test, feature(new_uninit))]
 #![feature(nonnull_slice_from_raw_parts)]
-#![feature(option_result_unwrap_unchecked)]
 #![feature(pattern)]
 #![feature(ptr_internals)]
 #![feature(receiver_trait)]

library/core/src/option.rs

@@ -800,19 +800,17 @@ impl<T> Option<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(option_result_unwrap_unchecked)]
     /// let x = Some("air");
     /// assert_eq!(unsafe { x.unwrap_unchecked() }, "air");
     /// ```
     ///
     /// ```no_run
-    /// #![feature(option_result_unwrap_unchecked)]
     /// let x: Option<&str> = None;
     /// assert_eq!(unsafe { x.unwrap_unchecked() }, "air"); // Undefined behavior!
     /// ```
     #[inline]
     #[track_caller]
-    #[unstable(feature = "option_result_unwrap_unchecked", reason = "newly added", issue = "81383")]
+    #[stable(feature = "option_result_unwrap_unchecked", since = "1.58.0")]
     pub unsafe fn unwrap_unchecked(self) -> T {
         debug_assert!(self.is_some());
         match self {

library/core/src/result.rs

@@ -1096,19 +1096,17 @@ impl<T, E> Result<T, E> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(option_result_unwrap_unchecked)]
     /// let x: Result<u32, &str> = Ok(2);
     /// assert_eq!(unsafe { x.unwrap_unchecked() }, 2);
     /// ```
     ///
     /// ```no_run
-    /// #![feature(option_result_unwrap_unchecked)]
     /// let x: Result<u32, &str> = Err("emergency failure");
     /// unsafe { x.unwrap_unchecked(); } // Undefined behavior!
     /// ```
     #[inline]
     #[track_caller]
-    #[unstable(feature = "option_result_unwrap_unchecked", reason = "newly added", issue = "81383")]
+    #[stable(feature = "option_result_unwrap_unchecked", since = "1.58.0")]
     pub unsafe fn unwrap_unchecked(self) -> T {
         debug_assert!(self.is_ok());
         match self {
@@ -1130,19 +1128,17 @@ impl<T, E> Result<T, E> {
     /// # Examples
     ///
     /// ```no_run
-    /// #![feature(option_result_unwrap_unchecked)]
     /// let x: Result<u32, &str> = Ok(2);
     /// unsafe { x.unwrap_err_unchecked() }; // Undefined behavior!
     /// ```
     ///
     /// ```
-    /// #![feature(option_result_unwrap_unchecked)]
     /// let x: Result<u32, &str> = Err("emergency failure");
     /// assert_eq!(unsafe { x.unwrap_err_unchecked() }, "emergency failure");
     /// ```
     #[inline]
     #[track_caller]
-    #[unstable(feature = "option_result_unwrap_unchecked", reason = "newly added", issue = "81383")]
+    #[stable(feature = "option_result_unwrap_unchecked", since = "1.58.0")]
     pub unsafe fn unwrap_err_unchecked(self) -> E {
         debug_assert!(self.is_err());
         match self {

library/core/tests/lib.rs

@@ -59,7 +59,6 @@
 #![feature(const_raw_ptr_deref)]
 #![feature(never_type)]
 #![feature(unwrap_infallible)]
-#![feature(option_result_unwrap_unchecked)]
 #![feature(result_into_ok_or_err)]
 #![feature(ptr_metadata)]
 #![feature(once_cell)]