Ultralytics Code Refactor https://ultralytics.com/actions (#13153)

* Refactor code for speed and clarity

* Update dataloaders.py

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

---------

Signed-off-by: Glenn Jocher <glenn.jocher@ultralytics.com>

detect.py

@@ -97,6 +97,7 @@ def run(
     dnn=False,  # use OpenCV DNN for ONNX inference
     vid_stride=1,  # video frame-rate stride
 ):
+    """Runs YOLOv5 detection inference on various sources like images, videos, directories, streams, etc."""
     source = str(source)
     save_img = not nosave and not source.endswith(".txt")  # save inference images
     is_file = Path(source).suffix[1:] in (IMG_FORMATS + VID_FORMATS)