Rollup merge of rust-lang#97455 - JohnTitor:stabilize-toowned-clone-into, r=dtolnay

Stabilize `toowned_clone_into`

Closes rust-lang#41263
FCP has been done: rust-lang#41263 (comment)

Author: Dylan-DPC

library/alloc/src/borrow.rs

@@ -67,14 +67,13 @@ pub trait ToOwned {
     /// Basic usage:
     ///
     /// ```
-    /// # #![feature(toowned_clone_into)]
     /// let mut s: String = String::new();
     /// "hello".clone_into(&mut s);
     ///
     /// let mut v: Vec<i32> = Vec::new();
     /// [1, 2][..].clone_into(&mut v);
     /// ```
-    #[unstable(feature = "toowned_clone_into", reason = "recently added", issue = "41263")]
+    #[stable(feature = "toowned_clone_into", since = "1.63.0")]
     fn clone_into(&self, target: &mut Self::Owned) {
         *target = self.to_owned();
     }

library/std/src/lib.rs

@@ -298,7 +298,6 @@
 #![feature(map_try_insert)]
 #![feature(new_uninit)]
 #![feature(thin_box)]
-#![feature(toowned_clone_into)]
 #![feature(try_reserve_kind)]
 #![feature(vec_into_raw_parts)]
 //