patch applied (packages/pretty): vcat should behave like 'foldr ($$) empty', not 'foldr ($+$) empty', according to the documentation

[Ian Lynagh]

Thu Mar  4 02:24:10 PST 2010  Benedikt Huber 
  * vcat should behave like 'foldr ($$) empty', not 'foldr ($+$) empty', according to the documentation

    M ./Text/PrettyPrint/HughesPJ.hs -1 +1

View patch online:
http://darcs.haskell.org/cgi-bin/darcsweb.cgi?r=packages/pretty;a=darcs_commitdiff;h=20100304102410-ae213-1d38e20978108b44b6b37a76024c003eb76f6989.gz