Add background coloring to nvim line number.
Add background coloring to nvim line number.

This change allows me to quickly see what line I am on.

This is a small UI feature I really enjoyed while I was using the
gruvbox theme for emacs. Working with Nick Cronquist we were able to
figure out how to replicate this tweak.

KyleOndy/dotfiles,KyleOndy/dotfiles,KyleOndy/dotfiles