Fixed a bug in the background image-set function

[max-kot]

Hi! When I used your plugin with gulp, I found some issue width image-set function with background property.

My bug was about additional adding of background-repeat, background-position and background-size and poproperties for additional url.

Input:

.test {
	background-color: var(--color-dark);
	background-image: image-set(
		url("../images/cover.png") type("image/png") 1x,
		url("../images/[email protected]") type("image/png") 2x,
		url("../images/[email protected]") type("image/png") 3x
		);
	background-position: center;
	background-size: cover;
	background-repeat: no-repeat;
}

Output:

.test {
	background: image-set( url("../images/cover.png") type("image/png") 1x, url("../images/[email protected]") type("image/png") 2x no-repeat center/cover, url("../images/[email protected]") type("image/png") 3x ) no-repeat center/cover var(--color-dark);
}

So, I actually found out how to fix it, and with that fix the final output looks like this:

.test {
	background: image-set( url("../images/cover.png") type("image/png") 1x, url("../images/[email protected]") type("image/png") 2x, url("../images/[email protected]") type("image/png") 3x ) no-repeat center/cover var(--color-dark);
}