The panics would occur because set_style
would draw outside of the the surface.
Both occured using `find_prev` or `till_prev`
In my case the first panic! would appear
in a terminal with around 80 columns
in helix/README.md going to the end of the file
with `geglf(`
the second with `geglfX`
The off by one fix ensures that `find_nth_prev`
starts at the first character to the left
e2d780f993