Issue python#24225: Within idlelib files, update idlelib module names.

This follows the previous patch that changed idlelib file names.
Class names that matched old module names are not changed.
Change idlelib imports in turtledemo.__main__.

Exception: config-extensions.def.  Previously, extension section
names, file names, and class names had to match.  Changing section
names would create cross-version conflicts in config-extensions.cfg
(user customizations).  Instead map old names to new file names
at point of import in editor.EditorWindow.load_extension.

Patch extensively tested with test_idle, idle_test.htest.py, a custom
import-all test, running IDLE in a console to catch messages,
and testing each menu item.  Based on a patch by Al Sweigart.

Author: terryjreedy

Lib/idlelib/__main__.py

@@ -3,6 +3,6 @@
 
 Run IDLE as python -m idlelib
 """
-import idlelib.PyShell
-idlelib.PyShell.main()
+import idlelib.pyshell
+idlelib.pyshell.main()
 # This file does not work for 2.7; See issue 24212.

Lib/idlelib/autocomplete.py

@@ -1,4 +1,4 @@
-"""AutoComplete.py - An IDLE extension for automatically completing names.
+"""autocomplete.py - An IDLE extension for automatically completing names.
 
 This extension can complete either attribute names of file names. It can pop
 a window with all available names, for the user to select from.
@@ -7,16 +7,16 @@
 import sys
 import string
 
-from idlelib.configHandler import idleConf
+from idlelib.config import idleConf
 
 # This string includes all chars that may be in an identifier
 ID_CHARS = string.ascii_letters + string.digits + "_"
 
 # These constants represent the two different types of completions
 COMPLETE_ATTRIBUTES, COMPLETE_FILES = range(1, 2+1)
 
-from idlelib import AutoCompleteWindow
-from idlelib.HyperParser import HyperParser
+from idlelib import autocomplete_w
+from idlelib.hyperparser import HyperParser
 
 import __main__
 
@@ -49,7 +49,7 @@ def __init__(self, editwin=None):
         self._delayed_completion_index = None
 
     def _make_autocomplete_window(self):
-        return AutoCompleteWindow.AutoCompleteWindow(self.text)
+        return autocomplete_w.AutoCompleteWindow(self.text)
 
     def _remove_autocomplete_window(self, event=None):
         if self.autocompletewindow: