Improve readability of `--help` output

[rrotter]

Description

cyan fg color used for options is difficult to read on a light background (green used for headers isn't great either, but that's arguably a matter of taste). --color=never has no effect here, as presumably the presence of --help disables other option parsing.

I propose that colors on the help output should be eliminated altogether, instead relying on a combination of bold and underscore where highligting is needed. Even if an option was added in the future to disable or alter these colors, discovering it would require using the help screen (it does not appear that this project has a man page).

If developers prefer keeping color on the help screen, then I alternatively propose that the colors be altered to something readable on a broader array of common terminal themes.

I'd be happy to submit a PR for this; submitting an issue first, per CONTRIBUTING.md.

[epage]

The great thing about the 3-bit terminal colors is that what they get rendered as is fully in the hands of the user.

The current color scheme is copied from cargo and other tools like uv have attempted to copy it as well. Both of those tools likely have a much wider install base than typos and I would defer to them on what works well. rust-lang/cargo#12578 is where I introduced colors into cargo --help but I was mostly reusing existing colors within Cargo. I included screenshots under various themes at rust-lang/cargo#12578 (comment) but I also explore many more themes than those when evaluating this.

--color=never has no effect here, as presumably the presence of --help disables other option parsing.

--help is processed immediately by the CLI parser while --color is an application level flag. Environment variables like NO_COLOR, CLICOLOR, and CLICOLOR_FORCE are respected.

[rrotter]

Thanks for the thoughtful reply.

It's a little surprising that NO_COLOR=1 typos -h strips bold formating as well, but it does solve my immediate issue.

[epage]

Flags like NO_COLOR apply to all ANSI escape codes. People just tend to refer to any use of ansi escape code as "color".