Added stripes() to outline-color and added computed value information for it

Author: SebastianZ

css-backgrounds-4/Overview.bs

@@ -190,7 +190,7 @@ Painting Area: the 'background-clip' property</h3>
 	Applies to: all elements
 	Inherited: no
 	Percentages: n/a
-	Computed Value: the computed color
+	Computed Value: the computed color and/or <<stripes()>> function
 	Animation type: see prose
 	</pre>
 

css-ui-4/Overview.bs

@@ -287,13 +287,14 @@ Animation type: by computed value
 
 <pre class="propdef">
 Name: outline-color
-Value: <<color>> | invert
+Value: [ <<color>> || <<stripes()>> ] | invert
 Initial: invert
 Applies to: all elements
 Inherited: no
 Percentages: N/A
 Computed value: The computed value for ''outline-color/invert'' is ''outline-color/invert''.
  For <<color>> values, see [[!CSS-COLOR-4#resolving-color-values]] in [[!CSS-COLOR-4]].
+ <<stripes()>> values are computed as defined in their definition.
 Animation type: by computed value
 </pre>