fix typo in ThreadedChildWatcher docs (GH-23277)

(cherry picked from commit 8836574a0f34ae81643c8af79bbb9062e332a4e3)

Co-authored-by: Thomas Grainger <tagrain@gmail.com>

diff --git a/Doc/library/asyncio-policy.rst b/Doc/library/asyncio-policy.rst
index 2e153d6fe2647f3f76783f008f43af28058d77fc..91f9822599d482f642c91c19e294dc56d492bf0d 100644 (file)
--- a/Doc/library/asyncio-policy.rst
+++ b/Doc/library/asyncio-policy.rst
@@ -209,7 +209,7 @@ implementation used by the asyncio event loop:
    It works reliably even when the asyncio event loop is run in a non-main OS thread.
 
    There is no noticeable overhead when handling a big number of children (*O(1)* each
-   time a child terminates), but stating a thread per process requires extra memory.
+   time a child terminates), but starting a thread per process requires extra memory.
 
    This watcher is used by default.