bpo-36766: Typos in docs and code comments (GH-13116)

diff --git a/Lib/idlelib/configdialog.py b/Lib/idlelib/configdialog.py
index 31520a3..4aaec13 100644
--- a/Lib/idlelib/configdialog.py
+++ b/Lib/idlelib/configdialog.py
@@ -2225,7 +2225,7 @@
      'General': '''
 General:
 
-AutoComplete: Popupwait is milleseconds to wait after key char, without
+AutoComplete: Popupwait is milliseconds to wait after key char, without
 cursor movement, before popping up completion box.  Key char is '.' after
 identifier or a '/' (or '\\' on Windows) within a string.