Re-de-confuse Thread start/run.

Author: jnthn

S17-concurrency.pod

@@ -657,7 +657,7 @@ It is also possible to create a thread object, and set it running later:
         say "A thread, you say?";
     });
     # later...
-    $thread.start();
+    $thread.run();
 
 Both approaches result in C<$thread> containing a C<Thread> object. At some
 point, C<join> should be called on the thread, from the thread that started