Update quickstart.jade

Author: kwalrath

public/docs/dart/latest/quickstart.jade

@@ -48,10 +48,8 @@ p.
   // Is browser really needed?
 
   .alert.is-helpful.
-    If you're using Dart's Dev channel, then your version of angular2
-    will be higher than alpha 6. That's fine.
-
-  // PENDING: Update once 1.9 is on stable channel.
+    Depending on your version of Dart, your version numbers (of angular2
+    and other packages) might be higher than shown above. That's fine.
 
 
 // STEP 2 - Import Angular ##########################