[css-images-4] Make cross-fade() have same order as color-mix() #9405

Author: svgeesus

css-images-4/Overview.bs

@@ -589,7 +589,7 @@ Combining images: the ''cross-fade()'' notation {#cross-fade-function}
 
 	<pre class=prod>
 		<dfn caniuse="css-cross-fade">cross-fade()</dfn> = cross-fade( <<cf-image>># )
-		<dfn>&lt;cf-image></dfn> = <<percentage [0,100]>>? && [ <<image>> | <<color>> ]
+		<dfn>&lt;cf-image></dfn> = [ <<image>> | <<color>> ] && <<percentage [0,100]>>? 
 	</pre>
 
 	The function represents an image generated by