Convert investigation to dataset

[monneyboi]

It wasn't obvious to me that datasets & investigations are both collections, and that an admin user can switch the type of collections.

I would be nice if this would be in the documentation.

[Rosencrantz]

Thanks @monneyboi

Really appreciate the feedback. Apologies for the long delay in getting back to you. We'll take a look at this and see if we can't update the documentation to be clearer.