chore: fix all clippy warnings across workspace

crates/quicproquo-kt/src/tree.rs

@@ -182,6 +182,7 @@ fn largest_power_of_two_less_than(n: usize) -> usize {
 }
 
 #[cfg(test)]
+#[allow(clippy::unwrap_used)]
 mod tests {
     use super::*;