doc: notice freecad customization an changelog

Change-Id: If019f12696db1c1661580e51b1920e637c52efec

Author: ein-shved

nixos/doc/manual/release-notes/rl-2411.section.md

@@ -878,6 +878,8 @@
 
 - `virtualisation.incus` module gained new `incus-user.service` and `incus-user.socket` systemd units. It is now possible to add a user to `incus` group instead of `incus-admin` for increased security.
 
+- `freecad` now supports addons and custom configuration in nix-way, which can be used by calling `freecad.customize`.
+
 ## Detailed Migration Information {#sec-release-24.11-migration}
 
 ### `sound` options removal {#sec-release-24.11-migration-sound}