[Petrache]

Originally Posted by Peter T. Daniels

Simply use Find-Replace (Ctrl-H). If you don't remember how you typed your
minus signs, just copy one of them and paste it into the Find box; then
type in the Replace With box whatever you want to replace them with; and
click Replace All.

Unfortunately, your solution don't work. Find-replace is changing characters inside text only! And it's impossible to select and replace that minus signs in front of the rows, because they are seen as bullets.