fix(modules/dgn-console): Udate description of psql options

modules/nixos/dgn-console.nix

@@ -23,11 +23,17 @@ in
     pg-upgrade-from = mkOption {
       type = lib.types.package;
       default = config.services.postgresql.package;
+      description = ''
+        Old postgresql package.
+      '';
     };
 
     pg-upgrade-to = mkOption {
       type = lib.types.package;
       default = pkgs.postgresql_15;
+      description = ''
+        New postgresql package.
+      '';
     };
   };