Update index.bs

Co-authored-by: Kagami Sascha Rosylight <[email protected]>

Author: youennf

index.bs

@@ -1470,7 +1470,7 @@ interface ReadableStreamDefaultController {
   readonly attribute unrestricted double? desiredSize;
 
   undefined close();
-  undefined enqueue(optional any chunk, optional StructuredSerializeOptions options = { });
+  undefined enqueue(optional any chunk, optional StructuredSerializeOptions options = {});
   undefined error(optional any e);
 };
 </xmp>