SectionName. These split class GetCfgSectionNameDialog from
configSectionNameDialog.py, temporarily renamed config_sec.py in 3.7.9a2.
More Query subclasses are planned.
tkinter.Variable class. They replace old methods trace_variable, trace,
trace_vdelete and trace_vinfo that use obsolete Tcl commands and might
not work in future versions of Tcl.
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.