[Docs] what's the meaning of results of RTMW3D for 3D whole-body pose estimation

[Z-mingyu]

📚 The doc issue

the results:[[-147.5, -128.5, 261.5], [-154.0, -129.0, 268.0], [-142.0, -129.5, 268.0], [-162.5, -131.0, 265.0], [-134.0, -137.5, 265.5],...]
why x-axis and y-axis are negative number？And what's the unit of the coordinates?
Previously, the 2D coordinates output by RTMPose were all in the pixel coordinate system, such as [[887.1227, 228.5056],
[904.1030, 211.8202],
[870.3943, 212.1091],
[925.6238, 220.8870],
[849.7054, 220.0233],
[961.7643, 327.8932],
...]

Suggest a potential alternative/fix

No response