Rollup merge of #130290 - passcod:stabilise-entry-insert, r=ChrisDenton

Stabilize entry_insert

This stabilises `HashMap::Entry::insert_entry`, following the FCP in tracking issue #65225.

This was implemented in #64656 five years ago.

library/std/src/collections/hash/map.rs

@@ -2754,7 +2754,6 @@ impl<'a, K, V> Entry<'a, K, V> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(entry_insert)]
     /// use std::collections::HashMap;
     ///
     /// let mut map: HashMap<&str, String> = HashMap::new();
@@ -2763,7 +2762,7 @@ impl<'a, K, V> Entry<'a, K, V> {
     /// assert_eq!(entry.key(), &"poneyland");
     /// ```
     #[inline]
-    #[unstable(feature = "entry_insert", issue = "65225")]
+    #[stable(feature = "entry_insert", since = "CURRENT_RUSTC_VERSION")]
     pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V> {
         match self {
             Occupied(mut entry) => {
@@ -3097,7 +3096,6 @@ impl<'a, K: 'a, V: 'a> VacantEntry<'a, K, V> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(entry_insert)]
     /// use std::collections::HashMap;
     /// use std::collections::hash_map::Entry;
     ///
@@ -3109,7 +3107,7 @@ impl<'a, K: 'a, V: 'a> VacantEntry<'a, K, V> {
     /// assert_eq!(map["poneyland"], 37);
     /// ```
     #[inline]
-    #[unstable(feature = "entry_insert", issue = "65225")]
+    #[stable(feature = "entry_insert", since = "CURRENT_RUSTC_VERSION")]
     pub fn insert_entry(self, value: V) -> OccupiedEntry<'a, K, V> {
         let base = self.base.insert_entry(value);
         OccupiedEntry { base }