flake: add nix-community and stylix cachix as substituters

Author: awwpotato

flake.nix

@@ -91,6 +91,17 @@
     # keep-sorted end
   };
 
+  nixConfig = {
+    extra-substituters = [
+      "https://stylix.cachix.org"
+      "https://nix-community.cachix.org"
+    ];
+    extra-trusted-public-keys = [
+      "stylix.cachix.org-1:iTycMb+viP8aTqhRDvV5qjs1jtNJKH9Jjvqyg4DYxhw="
+      "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+    ];
+  };
+
   outputs =
     { flake-parts, systems, ... }@inputs:
     flake-parts.lib.mkFlake { inherit inputs; } {