docs: Add asyncio source code links (GH-16640)

diff --git a/Doc/library/asyncio-queue.rst b/Doc/library/asyncio-queue.rst
index e7775da..524560b 100644
--- a/Doc/library/asyncio-queue.rst
+++ b/Doc/library/asyncio-queue.rst
@@ -6,6 +6,10 @@
 Queues
 ======
 
+**Source code:** :source:`Lib/asyncio/queues.py`
+
+------------------------------------------------
+
 asyncio queues are designed to be similar to classes of the
 :mod:`queue` module.  Although asyncio queues are not thread-safe,
 they are designed to be used specifically in async/await code.