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
Bevore this PR `commands::find_prev_char` and `commands::till_prev_char` were triggerable through keys
but `seach::find_nth_next()` was hardcoded in `_find_char`.
The passed `fn` was nerver used. With this PR the passed `fn` is used.
The change in search.rs resolves an off by one error in the behivor of `find_nth_prev`
