📝 Update release notes

docs/en/docs/release-notes.md

@@ -2,6 +2,7 @@
 
 ## Latest Changes
 
+* ✨ Enable recent Material for MkDocs Insiders features. PR [#3710](https://github.com/tiangolo/fastapi/pull/3710) by [@tiangolo](https://github.com/tiangolo).
 * 🔥 Remove/clean extra imports from examples in docs for features. PR [#3709](https://github.com/tiangolo/fastapi/pull/3709) by [@tiangolo](https://github.com/tiangolo).
 * ➕ Update docs library to include sources in Markdown. PR [#3648](https://github.com/tiangolo/fastapi/pull/3648) by [@tiangolo](https://github.com/tiangolo).
 * ⬆ Add support for Python 3.9. PR [#2298](https://github.com/tiangolo/fastapi/pull/2298) by [@Kludex](https://github.com/Kludex).