Spelling fixes in comments [ci skip]

compiler/basicTypes/BasicTypes.hs

compiler/basicTypes/RdrName.hs

compiler/coreSyn/CoreSyn.hs

compiler/coreSyn/CoreUnfold.hs

compiler/deSugar/PmExpr.hs

compiler/iface/TcIface.hs

compiler/llvmGen/Llvm/AbsSyn.hs

compiler/llvmGen/Llvm/MetaData.hs

compiler/rename/RnTypes.hs

compiler/simplCore/Simplify.hs

compiler/stranal/WwLib.hs

compiler/typecheck/TcHsType.hs

compiler/typecheck/TcRnTypes.hs

compiler/typecheck/TcSMonad.hs

compiler/typecheck/TcSimplify.hs

compiler/typecheck/TcTyDecls.hs

compiler/types/TyCon.hs

compiler/utils/Pretty.hs

compiler/vectorise/Vectorise/Vect.hs

includes/RtsAPI.h