Add post-processing hook for structured-haskell-mode.
Add post-processing hook for structured-haskell-mode.

Fuuzetsu/cabal2nix,psibi/cabal2nix,jb55/cabal2nix,spencerjanssen/cabal2nix,bennofs/cabal2nix,gridaphobe/cabal2nix,dmalikov/cabal2nix