So recently I stumbled upon this symbol in one of Chopin's works, to be precise in "4 Mazurkas" (Op. 33 No. 1) in bars 14, 16 and 17.
Here's a link to the edition I'm talking about, and below is a screenshot of bar 14. I would post the other examples too, but this weird reputation system is not letting me.
I figured for myself that it is neither a trill or a mordent, since that usually would be above said note (that would be, in that case, a rest), but any help and/or correction is appreciated!