Fix typo in docs: 'created by th' -> 'created by the' (GH-21384)

diff --git a/Doc/library/asyncio-protocol.rst b/Doc/library/asyncio-protocol.rst
index 3079716..9dbd3ab 100644
--- a/Doc/library/asyncio-protocol.rst
+++ b/Doc/library/asyncio-protocol.rst
@@ -993,7 +993,7 @@
 An example of a subprocess protocol used to get the output of a
 subprocess and to wait for the subprocess exit.
 
-The subprocess is created by th :meth:`loop.subprocess_exec` method::
+The subprocess is created by the :meth:`loop.subprocess_exec` method::
 
     import asyncio
     import sys