Parts of askBool-generated questions can be unreadable

[koachan]

I noticed that parts of questions made by zinput can be unreadable when used with dark/light-themed terminal.
Sample program and its output:

const zinput = @import("zinput");

pub fn main() void {
    _ = zinput.askBool("The question is unreadable on light theme, and the y/n prompt is unreadable on dark theme") catch return;
}

[koachan]

I see that the library uses some hardcoded color values, would it be okay if it's changed into a more neutral combination?
If so then I'll prepare a PR for that.

zinput/src/main.zig

Line 48 in 5e0d781

try out.writeSeq(.{ Fg.Cyan, "? ", Fg.White, prompt, Fg.DarkGray, " (y/n) > " });