fix: attribute 'throw' missing

[Moraxyc]

       error: attribute 'throw' missing
       at /nix/store/bbfa2wvd0svlf0nlw78llkzv8w726vkv-source/flake.nix:34:28:
           33|         overlay = lib.warn "nur.overlay has been replaced by nur.overlays.default" overlay; # Added 2024-12-06
           34|         nixosModules.nur = lib.throw "nur.nixosModules.nur has been replaced by nur.modules.nixos.default"; # Added 2024-12-06
             |                            ^
           35|         hmModules.nur = lib.throw "nur.hmModules.nur has been replaced by nur.modules.home-manager.default"; # Added 2024-12-06
       Did you mean throwIf?

Have no idea why lib.throw doesn't point to builtins.throw, but the thing is that lib.throw doesn't exist, so we have to use builtins.throw

https://noogle.dev/f/lib/throw

[Moraxyc]

cc maintainer: @Pandapip1