Find & Replace should help you clean that up in your notes. Be careful not to remove any of the formatting you actually want, but it’s pretty safe to try things if you check them and Edit > Undo anything that turns out wrong. [It won’t hurt to make a fresh backup before you start too – File > Create Backup.]
I’ve written up some basic advice for this kind of editing – Edit Multiple Fields in Multiple cards at once - #6 by Danika_Dakika . If you want help with your particular string feel free to post what you find.