[docs] Update doc-string for buffer_as_messages method in Conversatio…

…nBufferWindowMemory (langchain-ai#18136)

minor fix stated in langchain-ai#18080

libs/langchain/langchain/memory/buffer_window.py

@@ -31,7 +31,7 @@ def buffer_as_str(self) -> str:
 
     @property
     def buffer_as_messages(self) -> List[BaseMessage]:
-        """Exposes the buffer as a list of messages in case return_messages is False."""
+        """Exposes the buffer as a list of messages in case return_messages is True."""
         return self.chat_memory.messages[-self.k * 2 :] if self.k > 0 else []
 
     @property