Save Keypoints visible to text (#3547)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

ultralytics/yolo/engine/results.py

@@ -290,8 +290,8 @@ class Results(SimpleClass):
                     seg = masks[j].xyn[0].copy().reshape(-1)  # reversed mask.xyn, (n,2) to (n*2)
                     line = (c, *seg)
                 if kpts is not None:
-                    kpt = kpts[j].xyn.reshape(-1).tolist()
-                    line += (*kpt, )
+                    kpt = torch.cat((kpts[j].xyn, kpts[j].conf[..., None]), 2) if kpts[j].has_visible else kpts[j].xyn
+                    line += (*kpt.reshape(-1).tolist(), )
                 line += (conf, ) * save_conf + (() if id is None else (id, ))
                 texts.append(('%g ' * len(line)).rstrip() % line)