Add option to highlight added and changed lines from git diff in the editor

So, Ctrl-k->git diff brings up the git diff view, that is just a view and is also 100% from git diff, including the skipped lines.

It would be very useful in certain cases to simply highlight, in green or red, the added and changed lines in the editor itself.
Ideally (this would be a big plus) optionally also including the last commit, so that if some changes have been added to the last commit (e.g., with the first commit or subsequent amends), they would still be highlighted.