update changelog

Author: RobinMalfait

packages/@headlessui-react/CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - Ensure `Element` is available before polyfilling to prevent crashes in non-browser environments ([#3493](https://github.com/tailwindlabs/headlessui/pull/3493))
+- Fix crash when using `instanceof HTMLElement` in some environments ([#3494](https://github.com/tailwindlabs/headlessui/pull/3494))
 
 ## [2.1.8] - 2024-09-12