nix: try nixd instead of nil

modules/common/rust.nix

@@ -1,5 +1,4 @@
 { pkgs, ... }: {
-  # TODO: install nil (nix language server)
   # TODO: check these out: https://github.com/RGBCube/ncc/blob/86212e148b2642a51814e873a81be73fbc494e86/modules/common/rust.nix#L15-L24
   environment.systemPackages = with pkgs; [
     (fenix.complete.withComponents [
@@ -11,21 +10,7 @@
     ])
     rust-analyzer-nightly
 
-    # for nil
-    nil
+    nixd
     nixfmt-rfc-style
   ];
-
-  # home-manager.sharedModules = [{
-  #   extraWrapperArgs = [
-  #     "--suffix"
-  #     "LIBRARY_PATH"
-  #     ":"
-  #     "${lib.makeLibraryPath [ pkgs.stdenv.cc.cc pkgs.zlib ]}"
-  #     "--suffix"
-  #     "PKG_CONFIG_PATH"
-  #     ":"
-  #     "${lib.makeSearchPathOutput "dev" "lib/pkgconfig" [ pkgs.stdenv.cc.cc pkgs.zlib ]}"
-  #   ];
-  # }];
 }