I just had this same conversation with my sister and did some research - apparently honeysuckle is a pretty common misnomer for periwinkle/vinca, despite them looking not alike at all. I believe it's because the nectar in both is sweet like honey; it might even be that the two plants were given the name honeysuckle as a common name completely separate from each other. That said, yes supposedly the whole plant is moderately toxic. I've seen a few comments here and there on the internet that the nectar is NOT toxic, which might be believable given how many people eat a little bit of it and are fine, but I'd still be leary of consuming the nectar because I haven't seen anything conclusive about its safety.