Recommend `jar xf file.zip` for zips (#5993)

data/xView.yaml

 # YOLOv5 🚀 by Ultralytics, GPL-3.0 license
 # xView 2018 dataset https://challenge.xviewdataset.org
-# --------  DOWNLOAD DATA MANUALLY from URL above and unzip to 'datasets/xView' before running train command!  --------
+# --------  DOWNLOAD DATA MANUALLY and jar xf val_images.zip to 'datasets/xView' before running train command!  --------
 # Example usage: python train.py --data xView.yaml
 # parent
 # ├── yolov5