Previously, to use a green and red shade with `TintColor` you'd need to
pass `Positive` and `Negative`, respectively. This terminology always
tripped me up, because, for example, I'd often try to use something
like:
```
Button::new("icon_color", "Negative")
style(ButtonStyle::Tinted(TintColor::Negative))
.color(Color::Error)
.icon_color(Color::Error)
.icon(IconName::Trash),
)
```
...and due to `icon_color` taking `Color::Error`, I'd always get
`TintColor` wrong at a first try, because I would, out of muscle memory,
write `TintColor::Error`, which wouldn't compile. That's exactly the
change in this PR—`TintColor` now takes `Success` and `Error` instead of
`Positive` and `Negative`, for more consistency.
Release Notes:
- N/A
115aa43354