checkpoint-duckdb: handle calling .list on async checkpointer (#3022)

libs/checkpoint-postgres/langgraph/checkpoint/postgres/aio.py

@@ -385,7 +385,7 @@ class AsyncPostgresSaver(BasePostgresSaver):
             # we don't check in other methods to avoid the overhead
             if asyncio.get_running_loop() is self.loop:
                 raise asyncio.InvalidStateError(
-                    "Synchronous calls to AsyncSqliteSaver are only allowed from a "
+                    "Synchronous calls to AsyncPostgresSaver are only allowed from a "
                     "different thread. From the main thread, use the async interface. "
                     "For example, use `checkpointer.alist(...)` or `await "
                     "graph.ainvoke(...)`."