[scroll-animations-1] Make scroll-timeline and scroll-timeline-name support multiple timelines fixing w3c#7657

Author: flackr

scroll-animations-1/Overview.bs

@@ -283,41 +283,50 @@ spec: cssom-view-1; type: dfn;
 
 	<pre class='propdef'>
 	Name: scroll-timeline-name
-	Value: none | <<custom-ident>>
+	Value: none | <<custom-ident>>#
 	Initial: none
 	Applies to: [=scroll containers=]
 	Inherited: no
-	Computed value: the specified keyword
+	Computed value: the keyword ''scroll-timeline-name/none'' or a list of <<custom-ident>>s
 	Animation type: not animatable
 	</pre>
 
-	Specifies a name for the [=scroll progress timeline=]
+	Specifies names for the [=scroll progress timelines=]
 	associated with this [=scroll container=].
 	The axis for this timeline is given by 'scroll-timeline-axis'.
 
+	Note: The number of names listed here
+	determines the number of [=scroll progress timelines=]
+	associated with this element.
+
 ### Axis of a Scroll Progress Timeline: the 'scroll-timeline-axis' property ### {#scroll-timeline-axis}
 
 	<pre class='propdef'>
 	Name: scroll-timeline-axis
-	Value: block | inline | vertical | horizontal
+	Value: [ block | inline | vertical | horizontal ]#
 	Initial: block
 	Applies to: [=scroll containers=]
 	Inherited: no
-	Computed value: the specified keyword
+	Computed value: a list of the keywords specified
 	Animation type: not animatable
 	</pre>
 
-	Specifies an axis for the [=scroll progress timeline=]
+	Specifies an axis for each [=scroll progress timeline=]
 	associated with this [=scroll container=].
 	The name for this timeline is given by 'scroll-timeline-name'.
 
 	Values are as defined for ''scroll()''.
 
+	If 'scroll-timeline-name' has more names than 'scroll-timeline-axis' has specified axes,
+	the excess timelines use the last 'scroll-timeline-axis' value.
+	If 'scroll-timeline-name' has fewer names than 'scroll-timeline-axis' has specified axes,
+	the used 'scroll-timeline-axis' list is truncated.
+
 ### Scroll Timeline Shorthand: the 'scroll-timeline' shorthand ### {#scroll-timeline-shorthand}
 
 	<pre class='propdef shorthand'>
 	Name: scroll-timeline
-	Value: <<'scroll-timeline-name'>> || <<'scroll-timeline-axis'>>
+	Value: [ <<'scroll-timeline-name'>> || <<'scroll-timeline-axis'>> ]#
 	Applies to: [=scroll containers=]
 	Inherited: no
 	Animation type: not animatable