MultiSelectionPrompt allows adding children to a choice in a single call.

[mudnug]

Similar to AddChoices() and AddChoice(), it would be convenient for MultiSelectionPrompt to support AddChildren() in addition to Add Child().

IMultiSelectionItem<T> AddChildren(IEnumerable<T> children) would allow adding child choices in a single call

--Update-- I went about trying to implement this feature and found AddChoiceGroup() appears to be intended for this purpose...

I believe the API feels inconsistent here, but perhaps what would have helped with discovery was an example on the docs site.