`color.diff`, `color.ui`, or `--color`, and respecting the `auto`
settings of the former if we are going to a terminal). `%C(auto,...)`
is accepted as a historical synonym for the default (e.g.,
- `%C(auto,red)`). Specifying `%C(always,...) will show the colors
+ `%C(auto,red)`). Specifying `%C(always,...)` will show the colors
even when color is not otherwise enabled (though consider
just using `--color=always` to enable color for the whole output,
including this format and anything else git might color). `auto`