fix errors on nixos-rebuild

hosts/nixos-vm/home.nix

@@ -9,9 +9,9 @@ global-configs-dir = ../../global-configs;
 in {
   imports = [
     ../../global-home.nix
-    ${global-configs-dir}/plasma.nix
-    ${global-configs-dir}/fastfetch.nix
-    ${global-configs-dir}/zen-browser.nix
+    "${global-configs-dir}/plasma.nix"
+    "${global-configs-dir}/fastfetch.nix"
+    "${global-configs-dir}/zen-browser.nix"
   ];
 
   home.packages = with pkgs; [