Text under green diff color not visible in dark template

[Sander78 (Sander Datema)]

Just noticed by coincidence:

[codinghorror (Jeff Atwood)]

Oh yeah that’s real bad. @DeanMarkTaylor this is the severity of problem we are looking for with dark theme. Unreadable even with perfect vision. Cc @tgxworld for fix next week.

[tgxworld (Alan Tan)]

Fixed in

https://github.com/discourse/discourse/commit/3af5ab8c2c4267bf51bb70305562e11dc8ad283b