Fix: invalid link to chat model in openai platform docs (#11609)

There is some invalid link in open ai platform
[docs](https://python.langchain.com/docs/integrations/platforms/openai).
So i fixed it to valid links.
- `/docs/integrations/chat_models/openai` ->
`/docs/integrations/chat/openai`
- `/docs/integrations/chat_models/azure_openai` ->
`/docs/integrations/chat/azure_chat_openai`

Thanks! ☺️

docs/docs_skeleton/docs/integrations/platforms/openai.mdx

@@ -41,7 +41,7 @@ For a more detailed walkthrough of the `Azure` wrapper, see [here](/docs/integra
 
 ## Chat model
 
-See a [usage example](/docs/integrations/chat_models/openai).
+See a [usage example](/docs/integrations/chat/openai).
 
 ```python
 from langchain.chat_models import ChatOpenAI
@@ -51,7 +51,7 @@ If you are using a model hosted on `Azure`, you should use different wrapper for
 ```python
 from langchain.llms import AzureChatOpenAI
 ```
-For a more detailed walkthrough of the `Azure` wrapper, see [here](/docs/integrations/chat_models/azure_openai)
+For a more detailed walkthrough of the `Azure` wrapper, see [here](/docs/integrations/chat/azure_chat_openai)
 
 
 ## Text Embedding Model