message: Color: improve Opacity increase/decrease to better match maximum (255.0 / 15.0 = 17.0)
diff: @@ -172,12 +172,12 @@ enum class Opacity : uint8_t {
  };
  constexpr Opacity& operator++(Opacity& _value) noexcept {
  - _value = static_cast<Opacity>(std::min(static_cast<int>(_value) + 16, 0xFF));
  + _value = static_cast<Opacity>(std::min(static_cast<int>(_value) + 15, 0xFF));
  return _value;
  }
  constexpr Opacity& operator--(Opacity& _value) noexcept {
  - _value = static_cast<Opacity>(std::max(static_cast<int>(_value) - 16, 0));
  + _value = static_cast<Opacity>(std::max(static_cast<int>(_value) - 15, 0));
  return _value;
  }
  