Fix typo and naming format for extensions

tools/test_idf_py/extra_path/some_ext.py

@@ -0,0 +1,21 @@
+def action_extensions(base_actions, project_path):
+    def some_callback(ut_apply_config_name, ctx, args):
+        print("!!! From some subcommand")
+
+    def some_global_callback(ctx, global_args, tasks):
+        print("!!! From some global callback: %s" % global_args.some_extension_option)
+
+    return {
+        "global_options": [{
+            "names": ["--some-extension-option"],
+            "help": "Help for option --some-extension-option",
+            "default": "test",
+        }],
+        "global_action_callbacks": [some_global_callback],
+        "actions": {
+            "extra_subcommand": {
+                "callback": some_callback,
+                "help": "Help for some subcommand.",
+            },
+        },
+    }