[css-scrollbars-1] Call out 'color-scheme' specifically, since it mentions scrollbars specifically. w3c#6438

Author: fantasai

css-scrollbars-1/Overview.bs

@@ -100,9 +100,9 @@ scrollbar-color value set on the HTML body element are not propagated to the vie
 <dt><dfn>auto</dfn></dt>
 <dd>The user agent determines the colors of the scrollbar.
 It should follow platform conventions,
-but may adjust the colors depending on context and other properties,
-such as switching between light or dark colors
-to suit the surrounding color scheme.
+but may adjust the colors in accordance with 'color-scheme'
+or other contextual information
+to better suit the page.
 </dd>
 <dt><dfn><<color>></dfn></dt>
 <dd>