Auto merge of rust-lang#116866 - slanterns:inspect-stabilize, r=BurntSushi

Stabilize `result_option_inspect`

This PR stabilizes `result_option_inspect`:

```rust
// core::option

impl Option<T> {
    pub fn inspect<F: FnOnce(&T)>(self, f: F) -> Self;
}

// core::result

impl Result<T, E> {
    pub fn inspect<F: FnOnce(&T)>(self, f: F) -> Self;
    pub fn inspect_err<F: FnOnce(&E)>(self, f: F) -> Self;
}
```

<br>

Tracking issue: rust-lang#91345.
Implementation PR: rust-lang#91346.

Closes rust-lang#91345.

Author: bors

core/src/option.rs

@@ -1079,8 +1079,6 @@ impl<T> Option<T> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(result_option_inspect)]
-    ///
     /// let v = vec![1, 2, 3, 4, 5];
     ///
     /// // prints "got: 4"
@@ -1090,11 +1088,8 @@ impl<T> Option<T> {
     /// let x: Option<&usize> = v.get(5).inspect(|x| println!("got: {x}"));
     /// ```
     #[inline]
-    #[unstable(feature = "result_option_inspect", issue = "91345")]
-    pub fn inspect<F>(self, f: F) -> Self
-    where
-        F: FnOnce(&T),
-    {
+    #[stable(feature = "result_option_inspect", since = "CURRENT_RUSTC_VERSION")]
+    pub fn inspect<F: FnOnce(&T)>(self, f: F) -> Self {
         if let Some(ref x) = self {
             f(x);
         }

core/src/result.rs

@@ -835,16 +835,14 @@ impl<T, E> Result<T, E> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(result_option_inspect)]
-    ///
     /// let x: u8 = "4"
     ///     .parse::<u8>()
     ///     .inspect(|x| println!("original: {x}"))
     ///     .map(|x| x.pow(3))
     ///     .expect("failed to parse number");
     /// ```
     #[inline]
-    #[unstable(feature = "result_option_inspect", issue = "91345")]
+    #[stable(feature = "result_option_inspect", since = "CURRENT_RUSTC_VERSION")]
     pub fn inspect<F: FnOnce(&T)>(self, f: F) -> Self {
         if let Ok(ref t) = self {
             f(t);
@@ -858,8 +856,6 @@ impl<T, E> Result<T, E> {
     /// # Examples
     ///
     /// ```
-    /// #![feature(result_option_inspect)]
-    ///
     /// use std::{fs, io};
     ///
     /// fn read() -> io::Result<String> {
@@ -868,7 +864,7 @@ impl<T, E> Result<T, E> {
     /// }
     /// ```
     #[inline]
-    #[unstable(feature = "result_option_inspect", issue = "91345")]
+    #[stable(feature = "result_option_inspect", since = "CURRENT_RUSTC_VERSION")]
     pub fn inspect_err<F: FnOnce(&E)>(self, f: F) -> Self {
         if let Err(ref e) = self {
             f(e);