pkg/js: fix readme for pkg/js and prepare another release

pkg/js/README.md

Index: pkg/js/README.md
diff --git a/pkg/js/README.md b/pkg/js/README.md
index e28092384b4fb89bd61abf9ec474993b06c3314a..19162f8e3dc58b9a599f7ed030cdc612a2484958 100644
--- a/pkg/js/README.md
+++ b/pkg/js/README.md
@@ -57,16 +57,21 @@ class Location {
 }
 ```
 
-#### Maps
-
-Dart `Map` objects, including literals, are "opaque" in JavaScript.
-You must create Dart classes for each of these.
+#### JavaScript object literals
 
+Many JavaScript APIs take an object literal as an argument. For example:
 ```js
 // JavaScript
 printOptions({responsive: true});
 ```
 
+If you want to use `printOptions` from Dart, you cannot simply pass a Dart `Map`
+object – they are are "opaque" in JavaScript.
+
+
+Instead, create a Dart class with both the `@JS()` and
+`@anonymous` annotations.
+
 ```dart
 // Dart
 void main() {
@@ -77,6 +82,7 @@ void main() {
 external printOptions(Options options);
 
 @Js()
+@anonymous
 class Options {
   external bool get responsive;
 
@@ -86,7 +92,7 @@ class Options {
 
 ## Contributing and Filing Bugs
 
-Please file bugs and features requests on the [Github issue tracker](https://github.com/dart-lang/js-interop/issues).
+Please file bugs and features requests on the [Github issue tracker](https://github.com/dart-lang/sdk/issues).
 
 We also love and accept community contributions, from API suggestions to pull requests.
 Please file an issue before beginning work so we can discuss the design and implementation.