Effects: keep the isolate_lowest_one allow #4263 dropped (clippy 1.99, the pinned toolchain, still flags the manual form)

crates/effects/src/group.rs

@@ -116,6 +116,8 @@ pub const PATHFINDER_MAX_OVERLAPS: usize = 16_384;
 /// Fenwick tree of counts over `n` slots, for counting the active boxes of [`within_budget`].
 struct Counts(Vec<isize>);
 
+// `isolate_lowest_one` is still unstable in Rust 1.96, and the workspace builds on 1.95 (rust-version).
+#[allow(unknown_lints, clippy::manual_isolate_lowest_one)]
 impl Counts {
     fn add(&mut self, slot: usize, d: isize) {
         let mut i = slot + 1;