nixos/doc: add release note for Deepin Desktop Environment

nixos/doc/manual/release-notes/rl-2305.section.md

@@ -46,7 +46,10 @@ In addition to numerous new and upgraded packages, this release has the followin
 
 - [Cloudlog](https://www.magicbug.co.uk/cloudlog/), a web-based Amateur Radio logging application. Available as [services.cloudlog](#opt-services.cloudlog.enable).
 
+- [Deepin Desktop Environment](https://github.com/linuxdeepin/dde), an elegant, easy to use and reliable desktop environment. Availabe as [services.xserver.desktopManager.deepin](options.html#opt-services.xserver.desktopManager.deepin).
+
 - [fzf](https://github.com/junegunn/fzf), a command line fuzzyfinder. Available as [programs.fzf](#opt-programs.fzf.fuzzyCompletion).
+
 - [readarr](https://github.com/Readarr/Readarr), Book Manager and Automation (Sonarr for Ebooks). Available as [services.readarr](options.html#opt-services.readarr.enable).
 
 - [gemstash](https://github.com/rubygems/gemstash), a RubyGems.org cache and private gem server. Available as [services.gemstash](#opt-services.gemstash.enable).