Stylizing --help and errors

[bbkane]

Maybe I can take inspiration from https://rust-cli-recommendations.sunshowers.io/managing-colors-in-rust.html

[bbkane]

Ok, how I think I want to do this:

• create a styles struct to map meaning to colors and a Colorize func to add the colors.
• use that in help

I also want to style errors which has more problems:

• color comes from flags, but we might need to print an error before flags are resolved: create a color struct before that and replace it once we resolve flags
• errors can be nested and we need to format and color the tree: I'd like to eventually get Nushell style errors but for now use an interface that has a TermDisplay(color Color, size TermSize{width,height}) method and an Error method. When printing an error, check if it implements TermDisplay and print that if so
• will need to create my own Wrap function because I can't recursively call TermDisplay on nested errors otherwise? Maybe I can with Unwrap?