improved documentation of Signal.foldp
improved documentation of Signal.foldp

colinmccabe/core,Pisys/core,krisajenkins/core,laszlopandy/core,manleyjster/core,martinos/core,bradurani/core,alexiamcdonald/elm-core,isaacsanders/core,suryagaddipati/core,vilterp/core,rgrempel/core,simonh1000/core,rick68/core,laszlopandy/core,rick68/core,martinos/core,manleyjster/core,Pisys/core,colinmccabe/core,ThomasWeiser/core,bradurani/core,ThomasWeiser/core,rgrempel/core,vilterp/core,simonh1000/core,Dandandan/core,eeue56/core,Dandandan/core,eeue56/core,alexiamcdonald/elm-core,suryagaddipati/core,krisajenkins/core,isaacsanders/core