Add instance IsString ShowS where fromString = showString

Hello, It would be really nice to use OverloadedStrings when constructing a ShowS, for example in a definition of showsPrec in an instance for Show. The patch attached in the ticket[3544] adds the necessary instance to base/GHC/Show.lhs: instance IsString ShowS where fromString = showString Note that this does require TypeSynonymInstances. Discussion period 2 weeks. regards, Bas [3544] http://hackage.haskell.org/trac/ghc/ticket/3544