Clarify that a vocabulary's "Multiple select" setting is managed by the HS config

I was trying out the latest 5.x-3.x-dev version of Hierarchical Select and now that I made one of my vocabularies use it, this vocabulary cannot be saved as "Multiple select." Both the Multiple select and "Use the Hierarchical Select for form element.." options are unchecked but the HS form element still appears in the node edit form. I've tried editing the vocabulary multiple times and checking Multiple select but it always go blank no matter what I choose.