Initial support for adding body from signature

Language/Haskell/GhcMod/Gap.hs

@@ -25,6 +25,7 @@ module Language.Haskell.GhcMod.Gap (
   , errorMsgSpan
   , typeForUser
   , nameForUser
+  , occNameForUser
   , deSugar
   , showDocWith
   , GapThing(..)
@@ -354,6 +355,13 @@ nameForUser = pprOccName . getOccName
 nameForUser = pprOccName False . getOccName
 #endif
 
+occNameForUser :: OccName -> SDoc
+#if __GLASGOW_HASKELL__ >= 708
+occNameForUser = pprOccName
+#else
+occNameForUser = pprOccName False
+#endif
+
 deSugar :: TypecheckedModule -> LHsExpr Id -> HscEnv
          -> IO (Maybe CoreExpr)
 #if __GLASGOW_HASKELL__ >= 708