Always just executables and don't build haddock

- Doesn't inflate closure size to over 2GB, see #143
- The API docs aren't important and we're intending on deprecating the
  hackage package, see #161

default.nix

@@ -40,14 +40,17 @@ let
     ];
   };
 
-  build = pkgs.haskellPackages.nixfmt;
+  build = lib.pipe pkgs.haskellPackages.nixfmt [
+    haskell.lib.justStaticExecutables
+    haskell.lib.dontHaddock
+    (drv: lib.lazyDerivation { derivation = drv; })
+  ];
 in
 build
 // rec {
   packages = {
     nixfmt = build;
-    nixfmt-static = haskell.lib.justStaticExecutables packages.nixfmt;
-    nixfmt-deriver = packages.nixfmt-static.cabal2nixDeriver;
+    nixfmt-deriver = build.cabal2nixDeriver;
 
     nixfmt-shell = packages.nixfmt.env.overrideAttrs (oldAttrs: {
       buildInputs =

flake.nix

@@ -20,7 +20,7 @@
 
         apps.default = {
           type = "app";
-          program = "${self.packages.${system}.nixfmt-static}/bin/nixfmt";
+          program = "${result}/bin/nixfmt";
         };
 
         checks = result.checks;