users_guide/ghci: Fix heading
users_guide/ghci: Fix heading

shlevy/ghc,ezyang/ghc,oldmanmike/ghc,shlevy/ghc,ezyang/ghc,vikraman/ghc,GaloisInc/halvm-ghc,shlevy/ghc,snoyberg/ghc,sdiehl/ghc,shlevy/ghc,tjakway/ghcjvm,olsner/ghc,oldmanmike/ghc,snoyberg/ghc,mcschroeder/ghc,mcschroeder/ghc,mcschroeder/ghc,olsner/ghc,sgillespie/ghc,mcschroeder/ghc,vikraman/ghc,snoyberg/ghc,tjakway/ghcjvm,sdiehl/ghc,vTurbine/ghc,snoyberg/ghc,vTurbine/ghc,tjakway/ghcjvm,vikraman/ghc,snoyberg/ghc,mettekou/ghc,tjakway/ghcjvm,mettekou/ghc,gridaphobe/ghc,vikraman/ghc,shlevy/ghc,nushio3/ghc,mcschroeder/ghc,sgillespie/ghc,tjakway/ghcjvm,gridaphobe/ghc,gridaphobe/ghc,oldmanmike/ghc,snoyberg/ghc,mettekou/ghc,mettekou/ghc,sdiehl/ghc,oldmanmike/ghc,sdiehl/ghc,GaloisInc/halvm-ghc,gridaphobe/ghc,GaloisInc/halvm-ghc,shlevy/ghc,olsner/ghc,vTurbine/ghc,vTurbine/ghc,mcschroeder/ghc,nushio3/ghc,nushio3/ghc,gridaphobe/ghc,vTurbine/ghc,GaloisInc/halvm-ghc,snoyberg/ghc,ezyang/ghc,mettekou/ghc,sgillespie/ghc,olsner/ghc,sgillespie/ghc,sgillespie/ghc,gridaphobe/ghc,nushio3/ghc,gridaphobe/ghc,nushio3/ghc,oldmanmike/ghc,sdiehl/ghc,GaloisInc/halvm-ghc,sgillespie/ghc,GaloisInc/halvm-ghc,vTurbine/ghc,ezyang/ghc,nushio3/ghc,vikraman/ghc,shlevy/ghc,ezyang/ghc,tjakway/ghcjvm,mettekou/ghc,oldmanmike/ghc,sgillespie/ghc,ezyang/ghc,sdiehl/ghc,olsner/ghc,oldmanmike/ghc,olsner/ghc,sdiehl/ghc,tjakway/ghcjvm,GaloisInc/halvm-ghc,mettekou/ghc,vikraman/ghc,vTurbine/ghc,mcschroeder/ghc,olsner/ghc,nushio3/ghc,ezyang/ghc,vikraman/ghc