bpo-33649: Add low-level APIs index. (GH-9364)

diff --git a/Doc/library/asyncio.rst b/Doc/library/asyncio.rst
index 9f45f74..7895826 100644
--- a/Doc/library/asyncio.rst
+++ b/Doc/library/asyncio.rst
@@ -43,12 +43,13 @@
   with async/await syntax.
 
 
-Reference
----------
+.. We use the "rubric" directive here to avoid creating
+   the "Reference" subsection in the TOC.
 
-.. rubric:: High-level APIs
+.. rubric:: Reference
 
 .. toctree::
+   :caption: High-level APIs
    :maxdepth: 1
 
    asyncio-task.rst
@@ -58,9 +59,8 @@
    asyncio-queue.rst
    asyncio-exceptions.rst
 
-.. rubric:: Low-level APIs
-
 .. toctree::
+   :caption: Low-level APIs
    :maxdepth: 1
 
    asyncio-eventloop.rst
@@ -69,10 +69,10 @@
    asyncio-policy.rst
    asyncio-platforms.rst
 
-.. rubric:: Guides and Tutorials
-
 .. toctree::
+   :caption: Guides and Tutorials
    :maxdepth: 1
 
    asyncio-api-index.rst
+   asyncio-llapi-index.rst
    asyncio-dev.rst