Re-generate Haskell packages with cabal2nix.

pkgs/applications/window-managers/xmonad/default.nix

@@ -1,3 +1,5 @@
+# This file was auto-generated by cabal2nix. Please do NOT edit manually!
+
 { cabal, extensibleExceptions, filepath, mtl, utf8String, X11 }:
 
 cabal.mkDerivation (self: {
@@ -14,12 +16,10 @@ cabal.mkDerivation (self: {
     mkdir -p $out/share/man/man1
     mv "$out/"**"/man/"*.1 $out/share/man/man1/
   '';
-
   patches = [
     # Patch to make xmonad use XMONAD_{GHC,XMESSAGE} (if available).
     ./xmonad_ghc_var_0.11.patch
   ];
-
   meta = {
     homepage = "http://xmonad.org";
     description = "A tiling window manager";