[css-animations-2] Fix animation-timeline computed value line

Author: fantasai

css-animations-2/Overview.bs

@@ -617,9 +617,13 @@ Initial: auto
 Applies to: all elements
 Inherited: no
 Percentages: N/A
-Computed value: list, each item either a case-sensitive [=css identifier=] or
-    the keywords ''single-animation-timeline/none'',
-    ''single-animation-timeline/auto''.
+Computed value: list, each item either
+    the keyword ''single-animation-timeline/none'',
+    the keyword ''single-animation-timeline/auto'',
+    a case-sensitive [=css identifier=],
+    a computed ''scroll()'' function,
+    or
+    a computed ''view()'' function
 Canonical order: per grammar
 Animation Type: not animatable
 </pre>