🚀 16 colour theme

[WhyNotHugo]

Context

I've gone through the effort of configuring delta to be readable on light mode and on dark mode by using separate themes.

The way this works is that delta uses specific colours when rendering depending on the system theme, but if the system theme changes after it renders (for example, while I'm scrolling through a 500 line diff, or when I have a diff next for reference next to my editor) the colours remain the same, and become unreadable with the new terminal theme.

In order words: when the system theme transitions to dark theme, the text previously rendered by delta remains dark, and is not dark-on-dark and becomes unreadable.

Example content rendered in dark mode:

The same terminal when the theme changes:

Feature request

I'd like to see support for 16colour themes. That is, themes which use the regular colours:

Value	Color
\e[0;30m	Black
\e[0;31m	Red
\e[0;32m	Green
\e[0;33m	Yellow
\e[0;34m	Blue
\e[0;35m	Purple
\e[0;36m	Cyan
\e[0;37m	White

If these colours are used, when the terminal's colour theme changes, the colours automatically update to the new theme.

This is what ls does, for example. If the terminal theme changes after it renders, the colours update accordingly.

Example ls rendered in light mode:

The same terminal when the theme changes:

Using the 16-colour theme also has high guarantees that the text is readable, since the colour in the theme will have been chosen with that intent.