Make more use of Fansi throughout the compiler

[lihaoyi]

This PR replaces Highlighting.scala and a bunch of ad-hoc color-management logic with Fansi, which does the same thing but in a tidier way

Mostly a call-for-call replacement, except we no longer juggle Console.RESETs like we previously did, and a lot of finicky imperative logic is gone since Fansi already implements it

There's definitely more that can be refactored to use fansi.Str instead of java.lang.String to model colored text, but this is a decent start

[som-snytt]

OnlyFansi

[lihaoyi]

The failure looks unrelated as far as I can tell, maybe a flake

[hamzaremmal]

@lihaoyi We will be splitting the REPL and the compiler in #24243. As the compiler is the center of everything and it should be as much self-contained as possible. It has been decided by Scala Core that we should not keep the shaded libraries in the compiler itself and will become normal dependencies in the REPL. As a result, this PR would not be accepted.

[lihaoyi]

Sounds good, feel free to close this then

[hamzaremmal]

Thanks for understanding.