Add documentation for Varying.toStream/fromStream
Add documentation for Varying.toStream/fromStream

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