Use nixpkgs-unstable instead of nixos-unstable

See nix-community/home-manager#5991

Author: schmir

flake.lock

@@ -6,7 +6,8 @@
     gpg240-nixpkgs.url = "github:nixos/nixpkgs?rev=5a8650469a9f8a1958ff9373bd27fb8e54c4365d";
 
     # Specify the source of Home Manager and Nixpkgs.
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    #nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    nixpkgs.url = "github:nixos/nixpkgs/nixpkgs-unstable";
     emacs-overlay = {
       url = "github:nix-community/emacs-overlay";
       inputs.nixpkgs.follows = "nixpkgs";