Change nixos registry definition

nixos registry entry now points to my config repo url

flake.nix

@@ -75,7 +75,16 @@
                 channel.enable = true;
                 registry = {
                   nixpkgs.flake = nixpkgs;
-                  nixos.flake = self;
+                  nixos = {
+                    from = {
+                      type = "indirect";
+                      id = "nixos";
+                    };
+                    to = {
+                      type = "git";
+                      url = "https://git.xenia.me.uk/xenia/nixos.git?ref=main";
+                    };
+                  };
                   jupyter = {
                     from = {
                       type = "indirect";