asyncio: Fix spelling and typos.

Thanks to Vajrasky Kok for discovering some of them.
diff --git a/Lib/asyncio/windows_events.py b/Lib/asyncio/windows_events.py
index c667a1c..e6be9d1 100644
--- a/Lib/asyncio/windows_events.py
+++ b/Lib/asyncio/windows_events.py
@@ -1,4 +1,4 @@
-"""Selector and proactor eventloops for Windows."""
+"""Selector and proactor event loops for Windows."""
 
 import _winapi
 import errno