Deprecate old Anthropic and OpenAI providers in favor of "chat" versions of each

[JasonWeill]

Problem

See #391 and #308. In LangChain, the old Anthropic and OpenAI providers have been deprecated in favor of ChatAnthropic and ChatOpenAI respectively. The old providers remain for compatibility reasons.

Proposed Solution

Un-suppress warnings when users use the old providers, and guide them to use the new chat providers.

Alternatively, redirect anthropic and openai requests to the same models in their chat counterparts.

Update the documentation to reflect this change.

[haesleinhuepf]

Hi, I'd like to second this is an issue. At the moment, %%ai chatgpt... causes this warning and it would be great if it wasn't there.

C:\Users\rober\miniconda3\envs\t311\Lib\site-packages\langchain_community\llms\openai.py:1057: UserWarning: You are trying to use a chat model. This way of initializing it is no longer supported. Instead, please use: from langchain_community.chat_models import ChatOpenAI
warnings.warn(

[JasonWeill]

Pull request #551 addresses the warning you've seen above.