Update interfaces/html.idl (#21201)

Source: https://github.com/tidoust/reffy-reports/blob/8b21e71/ed/idl/html.idl
Build: https://travis-ci.org/tidoust/reffy-reports/builds/637580641
diff --git a/interfaces/html.idl b/interfaces/html.idl
index 2c0c489..374ce83 100644
--- a/interfaces/html.idl
+++ b/interfaces/html.idl
@@ -1904,7 +1904,6 @@
   attribute EventHandler onmouseout;
   attribute EventHandler onmouseover;
   attribute EventHandler onmouseup;
-  attribute EventHandler onwheel;
   attribute EventHandler onpause;
   attribute EventHandler onplay;
   attribute EventHandler onplaying;
@@ -1929,6 +1928,7 @@
   attribute EventHandler onwebkitanimationiteration;
   attribute EventHandler onwebkitanimationstart;
   attribute EventHandler onwebkittransitionend;
+  attribute EventHandler onwheel;
 };
 
 interface mixin WindowEventHandlers {