o1-mini: unsupported parameter

Firstly, thanks for this magnificient plugin.

I've been trying to use the o1-mini model but I get the following error:

```
Unsupported parameter: 'max_tokens' is not supported with this model. Use 'max_completion_tokens' instead.
```

I changed the configuration to add max_completion_tokens but it seems that the max_tokens is sent in the request.

anyone with similar issue?

The issue names no file, test, or entry point. Trace where ChatGPT.nvim builds the OpenAI request for the o1-mini model, then verify that the request no longer sends max_tokens and uses max_completion_tokens instead; done when the model request is accepted without the reported unsupported-parameter error.

Written by the indexing model from the issue text.