flake: Remove formatter excludes, as there are no more autogenerated files (#559)

flake.nix

@@ -112,34 +112,7 @@
                 };
               };
           };
-          formatter = let
+          formatter = pkgs.alejandra;
-            # We need to exclude the plugins/_sources/* files as they are autogenerated
-            # nix formatter only takes a derivation so we need to make a proxy that passes
-            # the correct flags
-            excludeWrapper = {
-              stdenv,
-              alejandra,
-              writeShellScript,
-              ...
-            }:
-              stdenv.mkDerivation {
-                pname = "alejandra-excludes";
-                inherit (alejandra) version;
-
-                dontUnpack = true;
-                dontBuild = true;
-                installPhase = let
-                  script = writeShellScript "alejandra-excludes.sh" ''
-                    ${alejandra}/bin/alejandra --exclude ./plugins/_sources "$@"
-                  '';
-                in ''
-                  mkdir -p $out/bin
-                  cp ${script} $out/bin/alejandra-excludes
-                '';
-              };
-          in
-            pkgs.callPackage excludeWrapper {};
-
           lib = import ./lib {
             inherit pkgs;
             inherit (pkgs) lib;