IDLE: Fix typos in docs and comments (GH-13749)

diff --git a/Lib/idlelib/delegator.py b/Lib/idlelib/delegator.py
index dc2a1aa..55c95da 100644
--- a/Lib/idlelib/delegator.py
+++ b/Lib/idlelib/delegator.py
@@ -14,7 +14,7 @@
 
     def resetcache(self):
         "Removes added attributes while leaving original attributes."
-        # Function is really about resetting delagator dict
+        # Function is really about resetting delegator dict
         # to original state.  Cache is just a means
         for key in self.__cache:
             try: