ankisyncd: mark module as deprecated

nixos/doc/manual/release-notes/rl-2405.section.md

@@ -17,6 +17,7 @@ In addition to numerous new and upgraded packages, this release has the followin
 - [maubot](https://github.com/maubot/maubot), a plugin-based Matrix bot framework. Available as [services.maubot](#opt-services.maubot.enable).
 
 - [Anki Sync Server](https://docs.ankiweb.net/sync-server.html), the official sync server built into recent versions of Anki. Available as [services.anki-sync-server](#opt-services.anki-sync-server.enable).
+The pre-existing [services.ankisyncd](#opt-services.ankisyncd.enable) has been marked deprecated and will be dropped after 24.05 due to lack of maintenance of the anki-sync-server softwares.
 
 ## Backward Incompatibilities {#sec-release-24.05-incompatibilities}
 

nixos/modules/services/misc/ankisyncd.nix

@@ -46,6 +46,12 @@ in
     };
 
     config = mkIf cfg.enable {
+      warnings = [
+        ''
+        `services.ankisyncd` has been replaced by `services.anki-sync-server` and will be removed after
+        24.05 because anki-sync-server(-rs and python) are not maintained.
+        ''
+      ];
       networking.firewall.allowedTCPPorts = mkIf cfg.openFirewall [ cfg.port ];
 
       systemd.services.ankisyncd = {