nixos/dendrite: rename settings.sync_api.search.enable option to sett… (#386393)

nixos/modules/services/matrix/dendrite.nix

···
           };
         };
         options.sync_api.search = {
-          enable = lib.mkEnableOption "Dendrite's full-text search engine";
+          enabled = lib.mkEnableOption "Dendrite's full-text search engine";
           index_path = lib.mkOption {
             type = lib.types.str;
             default = "${workingDir}/searchindex";
···
           If Dendrite is configured to use https, tlsCert and tlsKey must be provided.
 
           nix-shell -p dendrite --command "generate-keys --tls-cert server.crt --tls-key server.key"
+        '';
+      }
+      {
+        assertion = !(cfg.settings.sync_api.search ? enable);
+        message = ''
+          The `services.dendrite.settings.sync_api.search.enable` option
+          has been renamed to `services.dendrite.settings.sync_api.search.enabled`.
         '';
       }
     ];