Remove surplus extensions

Author: newhoggy

prettyprinter/bench/LargeOutput.hs

@@ -1,7 +1,5 @@
 {-# LANGUAGE DeriveGeneric        #-}
-{-# LANGUAGE FlexibleInstances    #-}
 {-# LANGUAGE OverloadedStrings    #-}
-{-# LANGUAGE TypeSynonymInstances #-}
 
 {-# OPTIONS_GHC -fno-warn-orphans #-}