analogous method
A set of colors neighboring the input in u'v' chromatic direction.
Keeps the historical Material-style signature: count is the number of
returned colors (including the input) and divisions is the number of
wheel divisions, so the step is 360 / divisions degrees. Unlike the
old implementation, the wheel is the u'v' vector around white rather
than the warm-cool temperature cycle.
Behavior is undefined when count or divisions is 0.
When divisions < count, colors repeat.
Implementation
List<Hct> analogous({int count = 5, int divisions = 12}) =>
uv.analogous(input, count: count, step: 360.0 / divisions);