Changing github.com/vanadium/docs/blob/master links to vanadium.github.io

Change-Id: I6380336ece694de704dfb76ae57251b2c671b0de
diff --git a/lib/discovery.dart b/lib/discovery.dart
index 2ad9045..f66f064 100644
--- a/lib/discovery.dart
+++ b/lib/discovery.dart
@@ -35,7 +35,7 @@
   /// keys are Ids and values are Advertisement.
   ///
   /// SyncQL tutorial at:
-  ///    https://github.com/vanadium/docs/blob/master/tutorials/syncql-tutorial.md
+  ///    https://vanadium.github.io/syncbase/guides/syncql.html
   Future<Scanner> scan(String query);
 
   /// Advertise the [Advertisement] to be discovered by [scan].