Setting NO_COLOR=1 still prints without unicode in a non-tty context

[TheNeikos]

Setting NO_COLOR=1 (or 0) does not change the printing behavior in a no-tty situation.

This code seems to be why:

miette/src/handlers/theme.rs

Lines 70 to 80 in 59c8161

	impl Default for GraphicalTheme {
	fn default() -> Self {
	match std::env::var("NO_COLOR") {
	_ if !std::io::stdout().is_terminal() || !std::io::stderr().is_terminal() => {
	Self::none()
	}
	Ok(string) if string != "0" => Self::unicode_nocolor(),
	_ => Self::unicode(),
	}
	}
	}

It indiscriminately causes the theme to be set as ascii/no colors, no matter what the env variable says.

This is unfortunate, as I am testing for this output and having different settings in my CI and my CLI causes my tests to mismatch. I was hoping that some form of ENV variable would help me here, but it does not seem to depend on this.

Could this use-case be considered? I am not sure whether NO_COLOR should change whether one uses unicode/ascii. A new (non-standard) env variable is also not suuuper great.

---

Edit:

I just realized it's actually worse for me, as I cannot influence that match at all right now. Since with NO_COLOR its still UNICODE in my CLI.