Improved Usage example docstrings (#9075)

* Updated Usage examples

* Update detect.py

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

* Update predict.py

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

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

models/tf.py

@@ -7,7 +7,7 @@ Usage:
     $ python models/tf.py --weights yolov5s.pt
 
 Export:
-    $ python path/to/export.py --weights yolov5s.pt --include saved_model pb tflite tfjs
+    $ python export.py --weights yolov5s.pt --include saved_model pb tflite tfjs
 """
 
 import argparse

models/yolo.py

@@ -3,7 +3,7 @@
 YOLO-specific modules
 
 Usage:
-    $ python path/to/models/yolo.py --cfg yolov5s.yaml
+    $ python models/yolo.py --cfg yolov5s.yaml
 """
 
 import argparse