Fix typo (GH-12878)


"sychronization" -> "synchronization"
(cherry picked from commit 3e986de0d65e78901b55d4e500b1d05c847b6d5e)

Co-authored-by: Fredrik Averpil <fredrik@averpil.com>
diff --git a/Doc/library/asyncio-sync.rst b/Doc/library/asyncio-sync.rst
index 18b5629..291310d 100644
--- a/Doc/library/asyncio-sync.rst
+++ b/Doc/library/asyncio-sync.rst
@@ -17,7 +17,7 @@
   argument; use the :func:`asyncio.wait_for` function to perform
   operations with timeouts.
 
-asyncio has the following basic sychronization primitives:
+asyncio has the following basic synchronization primitives:
 
 * :class:`Lock`
 * :class:`Event`