vim mode cursor width in text cell

[scottdraves]

our text cells use proportional fonts, but the cursor is fixed width, for a space.
a space is narrower than most of the letters and the result looks bad.
ideally the cursor should change size based on what it's over.
if that's too hard, then just make it an "n" width.

codemirror/codemirror5#3256

[scottdraves]

[tomca32]

I believe this was fixed and can be closed

[scottdraves]

text cells only, not code.