Subprocess Protocols Documentation (GH-20950)

Should be "Subprocess Protocol instances" not "Datagram Protocol instances"

Author: kudavid

Doc/library/asyncio-protocol.rst

@@ -683,7 +683,7 @@ factories passed to the :meth:`loop.create_datagram_endpoint` method.
 Subprocess Protocols
 --------------------
 
-Datagram Protocol instances should be constructed by protocol
+Subprocess Protocol instances should be constructed by protocol
 factories passed to the :meth:`loop.subprocess_exec` and
 :meth:`loop.subprocess_shell` methods.