minor username formatting cleanup

options/common/libvirt.nix

@@ -1,7 +1,9 @@
 {
     config,
     ...
-}: {
+}: let
+    inherit (config.myOptions.other.system) username;
+in {
     virtualisation = {
         libvirtd = {
             enable = true;
@@ -16,7 +18,7 @@
 
     networking.firewall.trustedInterfaces = [ "virbr0" ];
 
-    users.users.${config.myOptions.other.system.username} = {
+    users.users.${username} = {
         extraGroups = [ "libvirtd" ];
     };
 }

options/common/networking.nix

@@ -28,5 +28,7 @@ in {
         services.NetworkManager-wait-online.wantedBy = lib.mkForce []; # default is [ "network-online.target" ]
     };
 
-    users.users.${username}.extraGroups = [ "networkmanager" ];
+    users.users.${username} = {
+        extraGroups = [ "networkmanager" ];
+    };
 }