bpo-33855: Still more edits and minimal tests for IDLE  (GH-7784)

Part 3 of 3, continuing PR #7689. This covers 14 idlelib modules and their tests,
rpc to zoomheight except for run (already done) and tooltip (being done separately).
diff --git a/Lib/idlelib/config_key.py b/Lib/idlelib/config_key.py
index 3a865f8..7f4bb49 100644
--- a/Lib/idlelib/config_key.py
+++ b/Lib/idlelib/config_key.py
@@ -291,8 +291,8 @@
 
 
 if __name__ == '__main__':
-    import unittest
-    unittest.main('idlelib.idle_test.test_config_key', verbosity=2, exit=False)
+    from unittest import main
+    main('idlelib.idle_test.test_config_key', verbosity=2, exit=False)
 
     from idlelib.idle_test.htest import run
     run(GetKeysDialog)