Diff highlighting looks bad on non-default themes
I use Dark
as "Syntax highlighting theme" and diff highlighting looks like this:
![Screenshot_2016-01-21_10.14.47](data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==)
Can we make sure that diff highlighting on all syntax highlighting themes looks at least usable?
cc @DouweM @rdavila @jschatz1