Ability to choose different provider for code completion and edit prediction

[dzervas]

I'm not sure if this makes sense but from what I've gathered the code completion and edit predictions are 2 distinct features. I've been using supermaven and I don't think that it supports edit predictions

In any case, it would be cool to be able to have different provider for each feature - especially if #42010 goes forward, since a bigger model could be used for predictions and a smaller, faster model for completion