XMonad.Prompt.Shell: improve 'env' documentation to cover goodgrue's problem
XMonad.Prompt.Shell: improve 'env' documentation to cover goodgrue's problem

Ignore-this: 7b652a280960cbdf99c236496ca091b0

darcs-hash:20111127231507-f7719-d135757d9c584e50d0cd4112d1a4d2fe87841f91

jthornber/XMonadContrib,jthornber/XMonadContrib