Use Unicode column width when calculating terminal cursor offset

[simnalamburt]

Respect unicode width

Reference

• https://github.com/ulyssa/iamb/issues/293
• https://github.com/ulyssa/iamb/pull/358

[ulyssa]

Thank you for fixing this, this is great! :sparkles: I realized while looking at how you did it that I forgot to also point you at the non-wrapping method too. I've updated it to do the same thing as the other two.