Broadcasting assignment idea

broadcast
development

#1

Given A::AbstractMatrix and b::AbstractVector one can broadcast assignments like:
A[:,cols] .= b.'
where cols may be a container of valid indices… However, I would like to broadcast assignment where cols is, WLOG, Vector{Vector{Int64}}. The idea is that broadcasting the assignment recognizes that it should broadcast the rows, but iterate through each of the elements of cols. Would that be nice feature to implement?