[css-scrollbars-1] inherited:yes per w3c#1957 refs

[css-scrollbars-1] inherited:yes per research and references in issue w3c#1957, resolving accordingly

Author: tantek

css-scrollbars-1/Overview.bs

@@ -43,10 +43,17 @@ Values</h3>
 Scrollbar Color Properties</h2>
 
 <pre class="propdef">
-Name: scrollbar-3dlight-color, scrollbar-arrow-color,  scrollbar-base-color, scrollbar-darkshadow-color, scrollbar-face-color, scrollbar-highlight-color, scrollbar-track-color, scrollbar-shadow-color
+Name: scrollbar-3dlight-color, 
+      scrollbar-arrow-color,  
+      scrollbar-base-color, 
+      scrollbar-darkshadow-color, 
+      scrollbar-face-color, 
+      scrollbar-highlight-color, 
+      scrollbar-track-color, 
+      scrollbar-shadow-color
 Value: normal | <<color>>
 Initial: normal
-Inherited: no (<a href="https://github.com/w3c/csswg-drafts/issues/1957">Issue 1957</a>)
+Inherited: yes
 Computed value: the computed color or the keyword normal
 Animation type: <a href="https://www.w3.org/TR/css3-transitions/#animtype-color">color</a>
 Applies to: block containers and boxes that establish a formatting context [same as elements that <a href=https://www.w3.org/TR/CSS22/visufx.html#propdef-overflow">'overflow' applies to</a>]