Fix comment

Author: AnatoliB

azure/durable_functions/models/DurableOrchestrationContext.py

@@ -775,8 +775,9 @@ def version(self) -> str:
 
     @staticmethod
     def _extract_version_from_history(history_events: List[HistoryEvent]) -> str:
-        """Extract the version from the execution started event in history,
-        or None if not found.
+        """Extract the version from the execution started event in history.
+        
+        Returns None if not found.
         """
         for event in history_events:
             if event.event_type == HistoryEventType.EXECUTION_STARTED: