bpo-33649: Add high-level APIs cheat-sheet (GH-9319)

diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst
index 7e09b16..d3cfd5f 100644
--- a/Doc/library/asyncio-task.rst
+++ b/Doc/library/asyncio-task.rst
@@ -165,7 +165,7 @@
    If *result* is provided, it is returned to the caller
    when the coroutine completes.
 
-   .. _asyncio-date-coroutine:
+   .. _asyncio_example_sleep:
 
    Example of coroutine displaying the current date every second
    during 5 seconds::
@@ -219,6 +219,8 @@
       If the *gather* itself is cancelled, the cancellation is
       propagated regardless of *return_exceptions*.
 
+   .. _asyncio_example_gather:
+
    Example::
 
       import asyncio
@@ -316,6 +318,8 @@
 
    If the wait is cancelled, the future *fut* is also cancelled.
 
+   .. _asyncio_example_waitfor:
+
    Example::
 
        async def eternity():
@@ -539,6 +543,8 @@
       suppressing cancellation completely is not common and is actively
       discouraged.
 
+      .. _asyncio_example_task_cancel:
+
       The following example illustrates how coroutines can intercept
       the cancellation request::