[bluebird] document .suppressUnhandledRejections

http://bluebirdjs.com/docs/api/suppressunhandledrejections.html

bluebird/bluebird.d.ts

@@ -317,6 +317,13 @@ class Bluebird<R> implements Bluebird.Thenable<R>, Bluebird.Inspection<R> {
    */
   cancel(): void;
 
+  /**
+   * Basically sugar for doing: somePromise.catch(function(){});
+   * 
+   * Which is needed in case error handlers are attached asynchronously to the promise later, which would otherwise result in premature unhandled rejection reporting.
+   */
+  suppressUnhandledRejections(): void;
+
   /**
    * Start the chain of promises with `Promise.try`. Any synchronous exceptions will be turned into rejections on the returned promise.
    *