Lint output uses illegible text color in light-mode terminals

[QuietMisdreavus]

It looks like swift-format prints its body text in bold-white when printing lint diagnostics, which is very difficult to read in my light-mode terminal theme:

Should this text be plain (uncolored) instead so that it can inherit the default text color from the active theme?

[allevato]

Indeed, it looks like we're explicitly doing boldWhite here and below. I'm actually shocked that this is the first report we've gotten of this!

If we want to match the compiler's diagnostics here, we should take out the styling on the filename/source location bit, and before the message, just do an ANSI reset followed by a bold without a color spec.