I agree that this is a documentation bug, but there is an easy way to split on any isspace character:
julia> const spaces = filter(isspace, Char(0):Char(0x10FFFF));
julia> split("Time flies like an arrow.(光陰矢の如し)", spaces)
5-element Array{SubString{UTF8String},1}:
"Time"
"flies"
"like"
"an"
"arrow.(光陰矢の如し)"
