Correct misleading documentation on Stack (thanks sdrodge)
Correct misleading documentation on Stack (thanks sdrodge)

Ignore-this: 518574016a9c15a741acdb6d2fa2e870

`Possibly empty' applies only to `Maybe (Stack a)', not `Stack a' described
there, so this is easier to understand.

darcs-hash:20110328001930-1499c-576faa6870919b21b02f5e6f16e413a2c197a3d5

Happy-Ferret/xmonad