config: use buildFirefoxXpiAddon from NUR

I didn't realize it is available.

flake.lock

@@ -122,29 +122,6 @@
         "type": "github"
       }
     },
-    "firefox-addons": {
-      "inputs": {
-        "flake-utils": "flake-utils_2",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "dir": "pkgs/firefox-addons",
-        "lastModified": 1702612985,
-        "narHash": "sha256-dnlw/lHJO2Fk/jUHzkz4dYKHF4nQxmHps9Jx8zldoo4=",
-        "owner": "rycee",
-        "repo": "nur-expressions",
-        "rev": "ae18cb76153e8dda888a313daac932ba358002ae",
-        "type": "gitlab"
-      },
-      "original": {
-        "dir": "pkgs/firefox-addons",
-        "owner": "rycee",
-        "repo": "nur-expressions",
-        "type": "gitlab"
-      }
-    },
     "flake-compat": {
       "flake": false,
       "locked": {
@@ -254,21 +231,6 @@
       }
     },
     "flake-utils_2": {
-      "locked": {
-        "lastModified": 1629284811,
-        "narHash": "sha256-JHgasjPR0/J1J3DRm4KxM4zTyAj4IOJY8vIl75v/kPI=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "c5d161cc0af116a2e17f54316f0bf43f0819785c",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
-    "flake-utils_3": {
       "inputs": {
         "systems": "systems_4"
       },
@@ -286,7 +248,7 @@
         "type": "github"
       }
     },
-    "flake-utils_4": {
+    "flake-utils_3": {
       "inputs": {
         "systems": "systems_5"
       },
@@ -304,7 +266,7 @@
         "type": "github"
       }
     },
-    "flake-utils_5": {
+    "flake-utils_4": {
       "inputs": {
         "systems": "systems_6"
       },
@@ -322,7 +284,7 @@
         "type": "github"
       }
     },
-    "flake-utils_6": {
+    "flake-utils_5": {
       "inputs": {
         "systems": "systems_7"
       },
@@ -343,7 +305,7 @@
     "helix-editor": {
       "inputs": {
         "crane": "crane",
-        "flake-utils": "flake-utils_4",
+        "flake-utils": "flake-utils_3",
         "nixpkgs": [
           "nixpkgs"
         ],
@@ -424,7 +386,7 @@
     },
     "neovim-flake": {
       "inputs": {
-        "flake-utils": "flake-utils_5",
+        "flake-utils": "flake-utils_4",
         "nixpkgs": [
           "neovim-nightly-overlay",
           "nixpkgs"
@@ -596,7 +558,7 @@
     "nixos-wsl": {
       "inputs": {
         "flake-compat": "flake-compat_3",
-        "flake-utils": "flake-utils_6",
+        "flake-utils": "flake-utils_5",
         "nixpkgs": [
           "nixpkgs"
         ]
@@ -731,8 +693,7 @@
         "devshell": "devshell",
         "disko": "disko",
         "emacs-overlay": "emacs-overlay",
-        "firefox-addons": "firefox-addons",
+        "flake-utils": "flake-utils_2",
-        "flake-utils": "flake-utils_3",
         "helix-editor": "helix-editor",
         "home-manager": [
           "home-manager-unstable"

flake.nix

@@ -74,10 +74,6 @@
     # Add a bunch of pre-compiled indices since mine are always crashing.
     nix-index-database.url = "github:nix-community/nix-index-database";
     nix-index-database.inputs.nixpkgs.follows = "nixpkgs";
-
-    # Someone has already solved downloading Firefox addons so we'll use it.
-    firefox-addons.url = "gitlab:rycee/nur-expressions?dir=pkgs/firefox-addons";
-    firefox-addons.inputs.nixpkgs.follows = "nixpkgs";
   };
 
   outputs = inputs@{ self, nixpkgs, ... }:
@@ -102,7 +98,7 @@
         # (including myself) that also relies on rycee's NUR instance. Overall,
         # it's a pain to setup so I'm not including this.
         (final: prev: {
-          inherit (inputs.firefox-addons.lib.${defaultSystem}) buildFirefoxXpiAddon;
+          inherit (final.nur.repos.rycee.firefox-addons) buildFirefoxXpiAddon;
           firefox-addons = final.callPackage ./pkgs/firefox-addons { };
         })