[Other]Update im.copy() to im in examples (#854)

* Update keypointdetection result docs

* Update im.copy() to im in examples

examples/vision/detection/yolov6/python/infer.py

@@ -52,7 +52,7 @@ if args.image is None:
 else:
     image = args.image
 im = cv2.imread(image)
-result = model.predict(im.copy())
+result = model.predict(im)
 print(result)
 
 # 预测结果可视化