transformers safetensors mixtral text-generation mergekit merge arxiv:2311.03099 arxiv:2306.01708 base_model:mistralai/Mixtral-8x7B-Instruct-v0.1 base_model:merge:mistralai/Mixtral-8x7B-Instruct-v0.1 base_model:mistralai/Mixtral-8x7B-v0.1 base_model:merge:mistralai/Mixtral-8x7B-v0.1 autotrain_compatible text-generation-inference endpoints_compatible region:us