Fix file watcher panic if event has no paths

crates/red_knot_workspace/src/watch/watcher.rs

@@ -209,8 +209,16 @@ impl Debouncer {
             return;
         }
 
+        let Some(path) = event.paths.into_iter().next() else {
+            tracing::debug!(
+                "Ignoring change event with kind '{:?}' without a path.",
+                event.kind
+            );
+            return;
+        };
+
         let kind = event.kind;
-        let path = match SystemPathBuf::from_path_buf(event.paths.into_iter().next().unwrap()) {
+        let path = match SystemPathBuf::from_path_buf(path) {
             Ok(path) => path,
             Err(path) => {
                 tracing::debug!(