bpo-33649: Fix markup; add another note that asyncio.run is 3.7+ (GH-9389)

diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst
index d597234..4f37296 100644
--- a/Doc/library/asyncio-task.rst
+++ b/Doc/library/asyncio-task.rst
@@ -20,7 +20,8 @@
 
 Coroutines declared with async/await syntax is the preferred way of
 writing asyncio applications.  For example, the following snippet
-of code prints "hello", waits 1 second, and then prints "world"::
+of code (requires Python 3.7+) prints "hello", waits 1 second,
+and then prints "world"::
 
     >>> import asyncio
 
diff --git a/Doc/library/asyncio.rst b/Doc/library/asyncio.rst
index bfc9700..1511b2f 100644
--- a/Doc/library/asyncio.rst
+++ b/Doc/library/asyncio.rst
@@ -8,7 +8,7 @@
 
 .. sidebar:: Hello World!
 
-   .. code-block:: python
+   ::
 
        import asyncio