users/jan: use mkmerge for nixpkgs overlays

flake.nix

@@ -59,6 +59,11 @@
                   ${nixos-rebuild}/bin/nixos-rebuild switch --flake .#${hostname}
                 '')
                 self.nixosConfigurations);
+              test = lib.recurseIntoAttrs (lib.mapAttrs
+                (hostname: machine: pkgs.writeShellScript "test-${hostname}" ''
+                  ${nixos-rebuild}/bin/nixos-rebuild test --flake .#${hostname}
+                '')
+                self.nixosConfigurations);
             });
 
           devShells = {

users/jan/default.nix

@@ -2,12 +2,15 @@
 
 let secrets = import ./secrets.nix; in
 {
-  nixpkgs.overlays = lib.mkAfter ((import ../../overlays) ++ [
-    inputs.wired.overlays.default
-    inputs.myneovim.overlays.default
-    inputs.vnetod.overlay
-    inputs.nil.overlays.default
-  ]);
+  nixpkgs.overlays = lib.mkMerge [
+    (lib.mkBefore (import ../../overlays))
+    (lib.mkAfter [
+      inputs.wired.overlays.default
+      inputs.myneovim.overlays.default
+      inputs.vnetod.overlay
+      inputs.nil.overlays.default
+    ])
+  ];
 
   users.users.jan = {
     isNormalUser = true;