typo

Author: tabatkins

web-animations-1/Overview.bs

@@ -4845,7 +4845,7 @@ interface KeyframeEffect : AnimationEffect {
     to the provided value after applying the following exceptions:
 
     *   If the provided value is not `null` or a syntactically valid
-        <pseudo-element-selector> the user agent must [=throw=]
+        <<pseudo-element-selector>> the user agent must [=throw=]
         a {{DOMException}} with error name {{TypeError}} and leave the
         [=target pseudo-selector=] of this [=animation effect=] unchanged.