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

[rs-sac]

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

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

Before:

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:

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.

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[rustbot]

The Miri subtree was changed

cc @rust-lang/miri