Use Default color instead of White

[spenserblack]

Allows the "white" color to have the greatest chance of being a dark,
visible color for light terminal themes. A macro is used to remap
White to Default to minimize size of the diff and prevent
contributors from needing to be familiar with the Default color on top
of the 8 standard colors.

For #33
Supersedes #611

TODO

• Review other uses of White where Default should be used

[spenserblack]

Sadly, I believe this does break the artistic intent of some logos on light terminals. For example, the Golang Gopher's eyes will have black sclera and white pupils on a light terminal. However, before this change, the white-on-white coloration of the gopher's eyes would give it the appearance of empty eye sockets.

I think that, to a certain extent, breakage of artistic intent is unavoidable on a light terminal, as many logos assume that empty space will be black. In other words, many of these logos were designed on and for a black "canvas".

[o2sh]

I think that, to a certain extent, breakage of artistic intent is unavoidable on a light terminal, as many logos assume that empty space will be black. In other words, many of these logos were designed on and for a black "canvas".

Yeah, dark terminals are the de facto standard and all logos should be designed with black "canvas" in mind first. Mapping White to default is the best compromise IMO.

[spenserblack]

I didn't modify num_to_color. Even though this a function with a very similar implementation in neofetch, num_to_color is pretty much only for user-specified overrides, and I think we can trust users to choose the correct foreground color.