How to stop sharing an Apple Notes folder

I must have accidentally hit "Share Folder", because now one of my Notes folders ("Daily") is replicated with a "Shared" folder of the same size. Every time I add a note to the Daily folder, the "Shared" folder increases in size by one.

It's not sharing with anyone - as far as I can tell - but how do I get rid of this Share folder without losing the notes inside it?