Mix of index-based and slice based indexing across different dimensions

[mbauman]

Make those idxs an array of CartesianIndex:

julia> idxs = CartesianIndex.([(1,2), (1,1)])
2-element Vector{CartesianIndex{2}}:
 CartesianIndex(1, 2)
 CartesianIndex(1, 1)

julia> A[idxs, :]
2×2 Matrix{Int64}:
 3  7
 1  5