asyncio docs: Fix dangling hyphen (GH-102227)

Currently this gets rendered with a dangling hyphen.
(cherry picked from commit 207e1c5)

Co-authored-by: Jelle Zijlstra <[email protected]>

Author: miss-islington

Doc/library/asyncio-eventloop.rst

@@ -510,8 +510,8 @@ Opening network connections
       When a server's IPv4 path and protocol are working, but the server's
       IPv6 path and protocol are not working, a dual-stack client
       application experiences significant connection delay compared to an
-      IPv4-only client.  This is undesirable because it causes the dual-
-      stack client to have a worse user experience.  This document
+      IPv4-only client.  This is undesirable because it causes the
+      dual-stack client to have a worse user experience.  This document
       specifies requirements for algorithms that reduce this user-visible
       delay and provides an algorithm.