asyncio doc: rewrite the callback hello world to use call_soon() instead of a
direct call.
diff --git a/Doc/library/asyncio-eventloop.rst b/Doc/library/asyncio-eventloop.rst
index c5dbb3b..95a8344 100644
--- a/Doc/library/asyncio-eventloop.rst
+++ b/Doc/library/asyncio-eventloop.rst
@@ -348,7 +348,7 @@
         loop.call_later(2, print_and_repeat, loop)
 
     loop = asyncio.get_event_loop()
-    print_and_repeat(loop)
+    loop.call_soon(print_and_repeat, loop)
     loop.run_forever()
 
 .. seealso::