'[\x91\x92]': "'"
Those are Unicode codepoints. For example:
Hmm, you’re right—those are not what I thought they were. It looks like those might be the codepoints for single quotes in Latin-1, but that seems like it won’t work in beets…
Yeah, if you want to match the accent characters—but if you want to match the “curly” quotes, these are they: