Attribution and CHANGELOG entry for sync/pr addition

CHANGELOG.org

@@ -20,6 +20,13 @@ performance cost (cavities?) in exchange for some extra sweetness?
 
 *** Bugfixes and improvements
 
+**** Document how to use sync/pr in tutorial
+
+The tutorial now includes a =sync/pr= example, allowing for easier
+integration with Racket's existing IO system.
+
+(Thank you Jonathan Frederickson!)
+
 **** Prevent replay attack in warden/incanter pairs
 
 Seals now "shatter" upon a single invocation.  This prevents sealed

goblins/scribblings/tutorial.scrbl

@@ -1,6 +1,7 @@
 #lang scribble/manual
 
 @;; Copyright 2020-2021 Christine Lemmer-Webber
+@;; Copyright 2021 Jonathan Frederickson
 @;;
 @;; Licensed under the Apache License, Version 2.0 (the "License");
 @;; you may not use this file except in compliance with the License.