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

* Update keypointdetection result docs

* Update im.copy() to im in examples

examples/vision/detection/yolov7/quantize/python/infer.py

@@ -71,7 +71,7 @@ model = fd.vision.detection.YOLOv7(
 
 # 预测图片检测结果
 im = cv2.imread(args.image)
-result = model.predict(im.copy())
+result = model.predict(im)
 print(result)
 
 # 预测结果可视化