Use dot operator for attribute sets with 1 element

modules/datasync.nix

@@ -31,7 +31,7 @@
           devices = [ "zion" ];
           versioning = {
             type = "simple";
-            params = { keep = "5"; };
+            params.keep = "5";
           };
         };
 
@@ -41,7 +41,7 @@
           devices = [ "zion" ];
           versioning = {
             type = "simple";
-            params = { keep = "5"; };
+            params.keep = "5";
           };
         };