Remove extraneous change

Author: sevanspowell

overlays/haskell.nix

@@ -560,7 +560,7 @@ final: prev: {
         # selected file ends in a `.yaml` it is assumed to be for `stackProject`.
         # If niether `stack.yaml` nor `cabal.project` exist `cabalProject` is
         # used (as it will use a default `cabal.project`).
-        project' = { src, projectFileName ? null, ... }@args:
+        project' = { src, projectFileName ? null, ... }@args: 
           let
             dir = __readDir (src.origSrcSubDir or src);
             exists = fileName: builtins.elem (dir.${fileName} or "") ["regular" "symlink"];