add clarifying comment in test

Author: cognifloyd

st2common/tests/unit/test_config_loader.py

@@ -545,6 +545,7 @@ def test_get_config_dynamic_config_item_under_additional_properties(self):
                     "host": "127.1.2.7",
                     "port": 8282,
                     # encrypted in datastore
+                    # (schema declares `secret: true` which triggers auto-decryption)
                     "token": "{{st2kv.system.k1_encrypted}}",
                 },
             }