[3.12] gh-103737: IDLE - Remove unneeded .keys() for dict iteration (GH-110960) (#111026)

gh-103737: IDLE - Remove unneeded .keys() for dict iteration (GH-110960)

Add comments where .keys() is needed.
Leave debugger usages along because situation is unclear as indicated in expanded comment.
Most testing is manual.
(cherry picked from commit baefbb21d9)

Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>

Lib/idlelib/config.py

@@ -597,7 +597,9 @@ class IdleConf:
         problem getting any core binding there will be an 'ultimate last
         resort fallback' to the CUA-ish bindings defined here.
         """
+        # TODO: = dict(sorted([(v-event, keys), ...]))?
         keyBindings={
+            # vitual-event: list of key events.
             '<<copy>>': ['<Control-c>', '<Control-C>'],
             '<<cut>>': ['<Control-x>', '<Control-X>'],
             '<<paste>>': ['<Control-v>', '<Control-V>'],
@@ -880,7 +882,7 @@ def _dump():  # htest # (not really, but ignore in coverage)
     line, crc = 0, 0
 
     def sprint(obj):
-        global line, crc
+        nonlocal line, crc
         txt = str(obj)
         line += 1
         crc = crc32(txt.encode(encoding='utf-8'), crc)
@@ -889,7 +891,7 @@ def _dump():  # htest # (not really, but ignore in coverage)
 
     def dumpCfg(cfg):
         print('\n', cfg, '\n')  # Cfg has variable '0xnnnnnnnn' address.
-        for key in sorted(cfg.keys()):
+        for key in sorted(cfg):
             sections = cfg[key].sections()
             sprint(key)
             sprint(sections)
@@ -908,4 +910,6 @@ if __name__ == '__main__':
     from unittest import main
     main('idlelib.idle_test.test_config', verbosity=2, exit=False)
 
-    # Run revised _dump() as htest?
+    _dump()
+    # Run revised _dump() (700+ lines) as htest?  More sorting.
+    # Perhaps as window with tabs for textviews, making it config viewer.