Update interfaces/html.idl (#27290)

Source: https://github.com/w3c/webref/blob/1cf1e7c/ed/idl/html.idl
Build: https://travis-ci.org/w3c/webref/builds/214185082
diff --git a/interfaces/html.idl b/interfaces/html.idl
index 5b30344..bb44c13 100644
--- a/interfaces/html.idl
+++ b/interfaces/html.idl
@@ -1440,8 +1440,8 @@
   undefined bezierCurveTo(unrestricted double cp1x, unrestricted double cp1y, unrestricted double cp2x, unrestricted double cp2y, unrestricted double x, unrestricted double y);
   undefined arcTo(unrestricted double x1, unrestricted double y1, unrestricted double x2, unrestricted double y2, unrestricted double radius);
   undefined rect(unrestricted double x, unrestricted double y, unrestricted double w, unrestricted double h);
-  undefined arc(unrestricted double x, unrestricted double y, unrestricted double radius, unrestricted double startAngle, unrestricted double endAngle, optional boolean anticlockwise = false);
-  undefined ellipse(unrestricted double x, unrestricted double y, unrestricted double radiusX, unrestricted double radiusY, unrestricted double rotation, unrestricted double startAngle, unrestricted double endAngle, optional boolean anticlockwise = false);
+  undefined arc(unrestricted double x, unrestricted double y, unrestricted double radius, unrestricted double startAngle, unrestricted double endAngle, optional boolean counterclockwise = false);
+  undefined ellipse(unrestricted double x, unrestricted double y, unrestricted double radiusX, unrestricted double radiusY, unrestricted double rotation, unrestricted double startAngle, unrestricted double endAngle, optional boolean counterclockwise = false);
 };
 
 [Exposed=(Window,Worker)]