Tracking issue: #2282

This fixes sharp gradients in SVG export as well as adding a test for the smoothness argument on gradient.sharp.

I have also noticed the following on which I would like your opinion: hue gradients (so gradients that involve hue rotations) can be... tricky, in some cases such as:

gradient.linear(
  color.hsl(0deg, 100%, 50%),
  color.hsl(359deg, 100%, 50%),
  color.hsl(0deg, 100%, 50%),
  relative: "parent",
  space: color.hsl
)

Will render as:

This is because it sees the part 0 -> 359 degrees as being a change of color, but the 359 -> 0 degrees as also being an increase, but so small that the color difference is literally zero. I was wondering whether I should annotate the doc to say that hsv and hsl gradients should use increase hue, or whether we could try and support this better? There is already a lot of code specifically for hsv and hsl gradients and I don't want to add potentially a lot, does anybody know how (others?) to handle that nicely?

Edit

As discussed on Discord, we will implement the ability to choose how to do hue interpolation, but that will be in part 6 as per #2282