Correct baseURL configuration usage (langchain-ai#9019)

Author: recabasic

libs/langchain-openai/src/chat_models.ts

@@ -2904,7 +2904,9 @@ export interface ChatOpenAIFields extends BaseChatOpenAIFields {
  *   timeout: undefined,
  *   maxRetries: 2,
  *   // apiKey: "...",
- *   // baseUrl: "...",
+ *   // configuration: {
+ *   //   baseURL: "...",
+ *   // }
  *   // organization: "...",
  *   // other params...
  * });