bg-img update (w3c#5242)

Author: alisonmaher

css-color-adjust-1/Overview.bs

@@ -383,8 +383,7 @@ Properties Affected by Forced Colors Mode {#forced-colors-properties}
 		<li>'text-shadow'
 	</pre>
 
-	Additionally, on <em>on user input controls (except button-like controls) only</em>,
-	'background-image'.
+	Additionally, 'background-image', unless the value is a 'url()' function.
 
 	'color-scheme' on the element must compute to ''light dark'',
 	to allow the user preference (see [[#forced|above]])