Update export.py docstring (#5689)

export.py

 # YOLOv5 🚀 by Ultralytics, GPL-3.0 license
 """
-Export a YOLOv5 PyTorch model to TorchScript, ONNX, CoreML, TensorFlow (saved_model, pb, TFLite, TF.js,) formats
-TensorFlow exports authored by https://github.com/zldrobit
+Export a YOLOv5 PyTorch model to other formats. TensorFlow exports authored by https://github.com/zldrobit
+
+Format                  | Example                   | Export `include=(...)` argument
+---                     | ---                       | ---
+PyTorch                 | yolov5s.pt                | -
+TorchScript             | yolov5s.torchscript.pt    | 'torchscript'
+ONNX                    | yolov5s.onnx              | 'onnx'
+CoreML                  | yolov5s.mlmodel           | 'coreml'
+TensorFlow SavedModel   | yolov5s_saved_model/      | 'saved_model'
+TensorFlow GraphDef     | yolov5s.pb                | 'pb'
+TensorFlow Lite         | yolov5s.tflite            | 'tflite'
+TensorFlow.js           | yolov5s_web_model/        | 'tfjs'
 
 Usage:
     $ python path/to/export.py --weights yolov5s.pt --include torchscript onnx coreml saved_model pb tflite tfjs
 
 Inference:
     $ python path/to/detect.py --weights yolov5s.pt
-                                         yolov5s.onnx  (must export with --dynamic)
+                                         yolov5s.torchscript.pt
+                                         yolov5s.onnx
+                                         yolov5s.mlmodel  (under development)
                                          yolov5s_saved_model
                                          yolov5s.pb
                                          yolov5s.tflite