Rollup merge of #140825 - rs-sac:ext, r=workingjubilee

Add Range parameter to `BTreeMap::extract_if` and `BTreeSet::extract_if`

This new parameter was requested in the btree_extract_if tracking issue:  rust-lang/rust#70530 (comment)

I attempted to follow the style used by `Vec::extract_if`.

Before:

```rust
impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
    #[unstable(feature = "btree_extract_if", issue = "70530")]
    pub fn extract_if<F>(&mut self, pred: F) -> ExtractIf<'_, K, V, F, A>
    where
        K: Ord,
        F: FnMut(&K, &mut V) -> bool;
}
```

After:

```rust
impl<K, V, A: Allocator + Clone> BTreeMap<K, V, A> {
    #[unstable(feature = "btree_extract_if", issue = "70530")]
    pub fn extract_if<F, R>(&mut self, range: R, pred: F) -> ExtractIf<'_, K, V, R, F, A>
    where
        K: Ord,
        R: RangeBounds<K>,
        F: FnMut(&K, &mut V) -> bool;
}
```

Related: #70530

—

While I believe I have adjusted all of the necessary bits, as this is my first attempt to contribute to Rust, I may have overlooked something out of ignorance, but if you can point out any oversight, I shall attempt to remedy it.

Author: workingjubilee

tests/pass/btreemap.rs

@@ -50,7 +50,7 @@ pub fn main() {
     test_all_refs(&mut 13, b.values_mut());
 
     // Test forgetting the extractor.
-    let mut d = b.extract_if(|_, i| *i < 30);
+    let mut d = b.extract_if(.., |_, i| *i < 30);
     d.next().unwrap();
     mem::forget(d);
 }