Full width unicode graphemes not handled correctly

[mcobzarenco]

Double width unicode grapheme do not seem to be handled correctly (not all grapheme have the same width in the terminal 🤷‍♂️).

I am not sure if this is out of scope. Otherwise 👍 for the great project.

[jmacdonald]

@mcobzarenco thanks for submitting this! This is definitely a legitimate bug; I think it's the cursor handling that's off here. I'll have a look at this when I get a moment!