Auto merge of #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;
}
```

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

Closes rust-lang/rust#91345.