📝 Update release notes

Author: tiangolo

docs/release-notes.md

@@ -5,6 +5,7 @@
 ### Features
 
 * ✨ Add support for extending typer apps without passing a name, add commands to the top level. PR [#1037](https://github.com/fastapi/typer/pull/1037) by [@patrick91](https://github.com/patrick91).
+    * New docs: [One File Per Command](https://typer.tiangolo.com/tutorial/one-file-per-command/).
 
 ### Internal