chore(docs): adding docs to core.ts and annotations.ts

modules/angular2/src/core/application_tokens.ts

@@ -1,5 +1,25 @@
 import {OpaqueToken} from 'angular2/di';
 import {CONST_EXPR} from 'angular2/src/facade/lang';
 
-export const appComponentRefToken: OpaqueToken = CONST_EXPR(new OpaqueToken('ComponentRef'));
-export const appComponentTypeToken: OpaqueToken = CONST_EXPR(new OpaqueToken('RootComponent'));
+/**
+ *  @private
+ */
+export const appComponentRefPromiseToken = CONST_EXPR(new OpaqueToken('Promise<ComponentRef>'));
+
+/**
+ * An opaque token representing the application root type in the {@link Injector}.
+ *
+ * ```
+ * @Component(...)
+ * @View(...)
+ * class MyApp {
+ *   ...
+ * }
+ *
+ * bootstrap(MyApp).then((appRef:ApplicationRef) {
+ *   expect(appRef.injector.get(appComponentTypeToken)).toEqual(MyApp);
+ * });
+ *
+ * ```
+ */
+export const appComponentTypeToken = CONST_EXPR(new OpaqueToken('RootComponent'));