Extensions17.hs.refact

[("tests/examples/Extensions17.hs:1:1: Error: Unused LANGUAGE pragma\nFound:\n  {-# LANGUAGE GeneralizedNewtypeDeriving, DeriveDataTypeable #-}\nWhy not:\n  {-# LANGUAGE DeriveDataTypeable #-}\n",[ModifyComment {pos = SrcSpan {startLine = 1, startCol = 1, endLine = 1, endCol = 64}, newComment = "{-# LANGUAGE DeriveDataTypeable #-}"}])]