warn when running console instead of repl

[lrytz]

---

re #19174 (comment)

[bishabosha]

I'd prefer a more "in your face" warning, but this works

[lrytz]

Happy to change it to whatever. There are plenty of emojis. Or make it an error?

[bishabosha]

I tried something like this maybe

streams.value.log.warn(s"${BOLD}###################################################################$RESET")
streams.value.log.warn(s"${BOLD}#                                                                 #$RESET")
streams.value.log.warn(s"${BOLD}# `console` uses the reference Scala version. Use `repl` instead. #$RESET")
streams.value.log.warn(s"${BOLD}#                                                                 #$RESET")
streams.value.log.warn(s"${BOLD}###################################################################$RESET")

[lrytz]

[SethTisue]

LGTM — I think the warning is better than an error, as it might still sometimes be handy to use console to see how the reference compiler handles something.

Also yay ascii art.