Do not use as default light_red color for error msgs

[musm]

discussion here #21433

What constitutes light_red (especially under non-standard terminal colors) seems to wildly inconsistent across terminals, so I think we should avoid using the color by default.

default terminal colorscheme

here are other schemes (note how inconsistent light_red is)

I propose we stick to default colors for the main colors used by Julia, and if the user finds the color not to their liking they can easily change it.

[KristofferC]

This will give a worse user experience for the majority of julia users (those that uses the default color settings in their terminal). These users are also those that are likely least tech savy and would have the most problems changing colors. The burden of changing colors should definitely lie on the user who actively chooses a colorschemes that breaks the convention of what color each ansi sequence should represent.

[musm]

I understand, however I think we should rethink not using bold by default in this case as the best middle ground that isn't terrible for everyone.

With the same argument the change to using non-bold has ruined the default user experience on windows ref #21531

from my perspective the best middle ground seems to be to default to bold

BTW I only noticed this since switching from 0.5 only recently

[KristofferC]

Using bold has other problems (for example, you cannot use yellow as a warning color because yellow bold is unreadable on white backgrounds). Using bold for large chunks of text is also wrong and annoying to read. When we switched away from bold, one of my friends said that "it was like being able to see again".

It would be a knee-jerk decision to change our defaults because Powershell doesn't seem to be able to display magenta? That's an issue and we should look at it, but that is a different discussion.

[musm]

I'm closing this PR in lieu of the issue #21531 since it will require more careful consideration on how to fix these underlying issues. But although the bold is not desirable by all; using non-bold seems to basically break the default color configuration on windows and produces the same problem as that of having the default be red (plus bold) instead of light_red as mentioned by @KristofferC on linux systems and mac. So by the same argument we should try to reconsider the best option that will uniformly work on all platforms decently.