Pretty: bugfix fillNB (#10735)
Pretty: bugfix fillNB (#10735)

This is a backport of a bug fix by Benedikt Huber (#2393), from commit
1e50748beaa4bd2281d323b18ea51c786bba04a1 in the pretty library.

From https://mail.haskell.org/pipermail/libraries/2008-June/009991.html:

    Law <l1> states that

    > sep (ps++[empty]++qs)   = sep (ps ++ qs)
    >         ...ditto hsep, hcat, vcat, fill...

    In the current implementation, this fails for the paragraph fill
    variants.

    > render' $ fsep [ text "c", text "c",empty, text "c", text "b"]
    >   where render' = renderStyle (Style PageMode 7 1.4)
    >> c c c
    >>     b

mfine/ghc,olsner/ghc,wxwxwwxxx/ghc,acowley/ghc,shlevy/ghc,shlevy/ghc,ml9951/ghc,vTurbine/ghc,nkaretnikov/ghc,wxwxwwxxx/ghc,tjakway/ghcjvm,sdiehl/ghc,siddhanathan/ghc,oldmanmike/ghc,wxwxwwxxx/ghc,ezyang/ghc,GaloisInc/halvm-ghc,da-x/ghc,mfine/ghc,mettekou/ghc,anton-dessiatov/ghc,siddhanathan/ghc,wxwxwwxxx/ghc,nkaretnikov/ghc,sgillespie/ghc,sdiehl/ghc,da-x/ghc,vTurbine/ghc,ezyang/ghc,GaloisInc/halvm-ghc,vikraman/ghc,mcschroeder/ghc,tjakway/ghcjvm,sdiehl/ghc,gridaphobe/ghc,wxwxwwxxx/ghc,mettekou/ghc,oldmanmike/ghc,shlevy/ghc,da-x/ghc,TomMD/ghc,ghc-android/ghc,anton-dessiatov/ghc,olsner/ghc,ml9951/ghc,ezyang/ghc,acowley/ghc,nkaretnikov/ghc,sgillespie/ghc,mettekou/ghc,ezyang/ghc,ml9951/ghc,snoyberg/ghc,sgillespie/ghc,nushio3/ghc,tjakway/ghcjvm,TomMD/ghc,olsner/ghc,vTurbine/ghc,nushio3/ghc,siddhanathan/ghc,mcschroeder/ghc,tjakway/ghcjvm,elieux/ghc,nushio3/ghc,GaloisInc/halvm-ghc,vTurbine/ghc,sdiehl/ghc,nushio3/ghc,vTurbine/ghc,shlevy/ghc,oldmanmike/ghc,vikraman/ghc,ezyang/ghc,shlevy/ghc,nushio3/ghc,oldmanmike/ghc,anton-dessiatov/ghc,ml9951/ghc,da-x/ghc,ghc-android/ghc,nushio3/ghc,gridaphobe/ghc,siddhanathan/ghc,olsner/ghc,elieux/ghc,acowley/ghc,mettekou/ghc,acowley/ghc,mfine/ghc,mcschroeder/ghc,vikraman/ghc,AlexanderPankiv/ghc,mfine/ghc,sdiehl/ghc,elieux/ghc,mfine/ghc,AlexanderPankiv/ghc,vTurbine/ghc,wxwxwwxxx/ghc,tjakway/ghcjvm,ghc-android/ghc,da-x/ghc,ml9951/ghc,da-x/ghc,GaloisInc/halvm-ghc,nkaretnikov/ghc,sgillespie/ghc,TomMD/ghc,GaloisInc/halvm-ghc,oldmanmike/ghc,nkaretnikov/ghc,snoyberg/ghc,GaloisInc/halvm-ghc,sgillespie/ghc,oldmanmike/ghc,elieux/ghc,nkaretnikov/ghc,acowley/ghc,nkaretnikov/ghc,TomMD/ghc,TomMD/ghc,mettekou/ghc,snoyberg/ghc,snoyberg/ghc,gridaphobe/ghc,vikraman/ghc,ml9951/ghc,ghc-android/ghc,sdiehl/ghc,TomMD/ghc,mfine/ghc,GaloisInc/halvm-ghc,AlexanderPankiv/ghc,mfine/ghc,elieux/ghc,shlevy/ghc,anton-dessiatov/ghc,ghc-android/ghc,olsner/ghc,elieux/ghc,AlexanderPankiv/ghc,siddhanathan/ghc,ezyang/ghc,snoyberg/ghc,siddhanathan/ghc,ml9951/ghc,gridaphobe/ghc,vikraman/ghc,vikraman/ghc,ezyang/ghc,acowley/ghc,oldmanmike/ghc,anton-dessiatov/ghc,snoyberg/ghc,da-x/ghc,anton-dessiatov/ghc,olsner/ghc,olsner/ghc,sgillespie/ghc,tjakway/ghcjvm,mcschroeder/ghc,gridaphobe/ghc,acowley/ghc,nushio3/ghc,AlexanderPankiv/ghc,TomMD/ghc,mcschroeder/ghc,AlexanderPankiv/ghc,vTurbine/ghc,tjakway/ghcjvm,mcschroeder/ghc,sdiehl/ghc,mettekou/ghc,vikraman/ghc,shlevy/ghc,gridaphobe/ghc,elieux/ghc,wxwxwwxxx/ghc,ghc-android/ghc,ml9951/ghc,anton-dessiatov/ghc,AlexanderPankiv/ghc,snoyberg/ghc,sgillespie/ghc,ghc-android/ghc,gridaphobe/ghc,siddhanathan/ghc,mettekou/ghc,mcschroeder/ghc