Color compiler warnings and errors

[maurobalbi]

Description of the change
This PR addresses #4152.

I haven't updated the golden tests yet, in case you would like to have some changes.

Example output:

Checklist:

• Added a file to CHANGELOG.d for this PR (see CHANGELOG.d/README.md)
• Added myself to CONTRIBUTORS.md (if this is my first contribution)
• Linked any existing issues or proposals that this pull request should close

[JordanMartinez]

If this was merged, would it affect purescript-psa at all?

[maurobalbi]

I'm pretty confident that purescript-psa uses the --json-errors flag to invoke purs, in which case this PR should have no effect on purescript-psa.

[JordanMartinez]

@rhendric You originally pushed back against similar work I did in #4156. Do you feel likewise about the work done here?

[rhendric]

No, my objection to #4156 was that it started to build an interface that overlapped with another interface we were discussing building; I don't see anything like that here. I don't really have an opinion one way or the other about this change.

[JordanMartinez]

I'll check this out and try it out locally sometime in the next few days. Otherwise, this looks good to me.

[JordanMartinez]

in the next few days

That was supposed to be maybe 3 days after I made that comment, but now it's almost been a week. Sorry about that. I'm currently building this PR's binary and going to test it out. However, I have friends coming by, so this might get postponed until tomorrow.

[maurobalbi]

No worries, all in due course! I'm already happy that this PR is being considered!

[JordanMartinez]

Here's a before and after of a warning and error using the following code:

module Main where

import Prelude

import Effect (Effect)
import Effect.Console (log)

main :: Effect Unit
main = do
  log "🍝"

foo :: Int -> String
foo x = "bar"

footer :: Int -> Int
footer x = "bar"

Type	State	Image
Warning	Before
Warning	After
Error	Before
Error	After

Two things immediately stand out:

• the content of the error message isn't indented like the content of the warning message. While we're here, I think that should be fixed
• I'm wondering if the warning color should be a slightly different color than what we're already using to highlight types and whatnot in the message. Perhaps a darker color, so that it stands a bit more in contrast to the rest of the message? However, I'm not sure that's needed because of the indentation.

If you're up for fixing the indentation, please do so and I'll approve it after that. If not, I'll approve this now since the PR does what you stated and debating about colors could delay this.

[maurobalbi]

Thanks for the review, I just checked it again and it looks like the indentation of warnings and errors is consistent. The difference comes from single vs multiple errors/warnings, as seen in the screenshots:

Type	Screenshot
Single error
Multiple errors
Single warning
Multiple warnings

I'm up for aligning those, my preference would be to add the indentation and newline to the single error/warning.
I tried some additional colors for the warnings, but nothing really stood out as a big improvement.
As a reference: https://en.wikipedia.org/wiki/ANSI_escape_code

Overall I guess there's a lot of bikeshedding to be had!

[JordanMartinez]

I'm up for aligning those, my preference would be to add the indentation and newline to the single error/warning.

Ok, please add the indentation for the single error/warning. Let's leave the colors as is. Thanks for doing this!

[JordanMartinez]

LGTM! Thanks!