Hello!

This adds emacs-diff-hl, which can be used to highlight changed lines
since the last commit the in versioning system.

The config below enables it for programming buffers:

--8<---------------cut here---------------start------------->8---
;;; Visualize changed lines
(add-hook 'prog-mode-hook 'turn-on-diff-hl-mode)
(add-hook 'vc-dir-mode-hook 'turn-on-diff-hl-mode)
(add-hook 'magit-post-refresh-hook 'diff-hl-magit-post-refresh)
--8<---------------cut here---------------end--------------->8---

Thanks,

Maxim