Mention loop_factory argument in docstring for asyncio.run() (#128288)

Lib/asyncio/runners.py

diff --git a/Lib/asyncio/runners.py b/Lib/asyncio/runners.py
index b9adf29..14397b4 100644
--- a/Lib/asyncio/runners.py
+++ b/Lib/asyncio/runners.py
@@ -177,6 +177,7 @@ def run(main, *, debug=None, loop_factory=None):
     running in the same thread.
 
     If debug is True, the event loop will be run in debug mode.
+    If loop_factory is passed, it is used for new event loop creation.
 
     This function always creates a new event loop and closes it at the end.
     It should be used as a main entry point for asyncio programs, and should