asyncio: Fix docs for default event loop (GH-14308)


When the Windows default event loop changed, `asyncio-policy.rst` was updated but `asyncio-eventloop.rst` was missed.
(cherry picked from commit 9ffca670ed4df42eb256e7144619a9d3a830e7c0)

Co-authored-by: Ben Darnell <ben@bendarnell.com>
1 file changed