README: fix hf download command dropping model_index.json
With huggingface_hub >= 1.0, --include takes one pattern per flag. In hf download MiniMaxAI/MiniMax-H3 --include "model_index.json" "FL2VA/*" "Ref2VA/*", only model_index.json goes to --include; the other two become positional file names, and the CLI warns "Ignoring --include since filenames have being explicitly set". The download then lacks the root model_index.json.
Passing all patterns as positional arguments works on both 0.x and 1.x, since several positional names are used as allow patterns. Checked on huggingface_hub 1.17.0 with --dry-run (both families: 163 files including model_index.json; FL2VA only: 82 files) and on 0.35.3 with a small real download. Repeating --include per pattern would fix 1.x but keep only the last pattern on 0.x.