Make good color choices in 256-color terminals about delta

[ELLIOTTCABLE]

As someone unfamiliar with Bat's usage of terminal-colour — is this possibly what's causing this issue on macOS for me?

Notably, bat --list-themes seems to be working fine, so I don't think it's a mis-configuration of the macOS Terminal, despite the README:

[dandavison]

Hi @ELLIOTTCABLE. Does Sublime Snazzy look OK in delta --compare-themes output? (btw: on master, I have changed the name of this command to delta --list-themes).

[ELLIOTTCABLE]

Looks about the same as the broken output above — all of the themes do. Odd!

Also strangely, delta --compare-themes is vastly slower than bat --list themes; the latter is effectively instant, whereas the former requires noticeable time for each theme enumerated — maybe another bug, or a related one, if this is a fork of bat? (If not a signifier of a bug, definitely not worth wasting time on, lmao. Of all commands -not- to prematurely optimize …)

[dandavison]

With #111 and #107 (which are in the current released version 0.0.17), delta fully supports 256-color terminal environments: it will automatically map 24-bit colors to their closest 8-bit approximation, and it is now easy to specify 8-bit compatible colors for all the command-line options that support colors. See README, 37cc69e commit message and the new output of --help for details.

@ELLIOTTCABLE is it behaving correctly for you on 0.0.17? I'm going to close this issue, but if it's not behaving correctly for you let's figure it out.