Respect $NO_COLOR variable

[Sohalt]

It would be cool for ripgrep to respect the NO_COLOR "standard", i.e. when $NO_COLOR is set, ripgrep should not colorize the output. See https://no-color.org

[BurntSushi]

I think I'm OK with this in principle. It should be implemented in termcolor as parts of its "auto" mode.

I think I've historically not done this because it's not clear to me how widespread NO_COLOR usage actually is.

[Sohalt]

Thanks, and sorry for not doing my research. I suspected ripgrep to use some library for colored terminal output and that would obviously be the better place to implement this. I've opened BurntSushi/termcolor#13.
As for how widespread NO_COLOR usage is, I can't really say, but I don't see a big downside to not implementing it. The variable name is fairly specific and even if it is set, one can override it, i.e. turn on colors, on a per program basis.
You can probably close this issue, since it needs to be implemented in termcolor and the change will eventually show up in ripgrep, when dependencies are updated.

[BurntSushi]

Please take further discussion to BurntSushi/termcolor#13