Language model provider guide

[isidorn]

Ref API https://github.com/microsoft/vscode/issues/250007

We need a guide for extensions that want to provide language models. So the producer, for the consumer part of this guide https://code.visualstudio.com/api/extension-guides/language-model

This does not have to be long.

Nick - do you have cycles to drive this. I am happy to sync and discuss about the content. Though we can wait first for Logan to finalize the API.

fyi @lramos15

[ntrogh]

@isidorn Suggest waiting for the API to be final.

[isidorn]

Makes sense.

[ntrogh]

Extension API sample: https://github.com/microsoft/vscode-extension-samples/tree/main/chat-model-provider-sample

[isidorn]

API is about to be finalized https://github.com/microsoft/vscode/pull/263415