Merge pull request w3c#314 from ewilligers/offset-rotate-computed

[motion] reverse does not appear in computed value

Author: ewilligers

motion-1/Overview.bs

@@ -1049,7 +1049,7 @@ Initial: auto
 Applies to: <a href="https://drafts.csswg.org/css-transforms-1/#transformable-element">transformable elements</a>
 Inherited: no
 Percentages: n/a
-Computed value: as specified
+Computed value: computed <<angle>> value, optionally preceded by auto
 Media: visual
 Animatable: yes
 </pre>