transformers gpt-neox causal-lm code dataset:bigcode/starcoderdata arxiv:2104.09864 arxiv:1910.02054 base_model:stabilityai/stablecode-completion-alpha-3b-4k base_model:finetune:stabilityai/stablecode-completion-alpha-3b-4k license:apache-2.0 model-index region:us