However, if you don't need them, I would remove them so that the user doesn't have to spend any time wondering which character it is. Even though you're processing them all after they type them and fixing them, the user has spent time and effort that they didn't need to, just picking which one it is.
IIRC, I chose to keep them when I did something like this, but I don't think I thought to accept the others and convert them automatically. That project is sunset now, so it's not an issue.
However, if you don't need them, I would remove them so that the user doesn't have to spend any time wondering which character it is. Even though you're processing them all after they type them and fixing them, the user has spent time and effort that they didn't need to, just picking which one it is.
IIRC, I chose to keep them when I did something like this, but I don't think I thought to accept the others and convert them automatically. That project is sunset now, so it's not an issue.