Update default output colorization for 6.1.0?

[johnkerl]

One of the UX aspects of Miller 6 is output colorization -- this mimics jq, for example:

This was released on-by-default in Miller 6, with opt-out via environment variables and/or .mlrrc.

So far, so good ... here is a planning/feedback question for 6.1.0, though, about the default colors, and what best defaults to use:

• The blue and orange (for keys and values, respectively) were chosen to both stand out against either a white or a black terminal background.
• They were also chosen to be differntiable from one another, across common varieties of human color vision (e.g. the red/green distinction).
• This (I hope) is enough to get started for most users, with further post-install customization via environment / .mlrrc as above.

However ...

• For anyone with a blue(ish) or orange(ish) terminal setup, the default isn't good.
• Are their better hard-coded (out-of-the-box) defaults than the current ones?
• Is there a reasonable heuristic to take shell coloring from the current environment for bash/zsh/etc users which would work at least sometimes?
• Instead of coloring keys/values, should we perhaps be just boldfacing keys and leaving values alone, or something similar perhaps -- maybe using the ANSI feature for 'brighten' or 'bold' using whatever color the user already has for text?

[johnkerl]

Here is an alternate idea, using bolding/underlinining for keys, and no decoration for values -- first is with -M to show the undecorated terminal colors, then after that CSV-output and JSON-output examples:

[johnkerl]

My thinking for 6.1.0 is that maybe:

• We still support all the color options as for 6.0.0
• We add choices for bold, underline, and reverse (as screenshotted above)
• We make the default behavior be bold for keys -- bold of whatever the user's foreground text color is -- and no decoration for values
• This will perhaps improve the out-of-the-box UX for first-time users while letting existing users keep whatever configs they have

[johnkerl]

#904

[johnkerl]

I'll go with bold-underline for keys and plain for values unless I hear otherwise ...