fix/update RCNN-family docstrings

[rizavelioglu]

Fixes #8228

[pytorch-bot]

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✅ You can merge normally! (5 Unrelated Failures)

As of commit 34da6e0 with merge base 315f315 ():

FLAKY - The following jobs failed but were likely due to flakiness present on trunk:

• Build Windows Conda / pytorch/vision / conda-py3_8-cpu (gh)
  Process completed with exit code 1.
• Build Windows Conda / pytorch/vision / conda-py3_8-cuda12_1 (gh)
  Process completed with exit code 1.
• CMake / linux (linux.g5.4xlarge.nvidia.gpu, cuda, 11.8) / linux-job (gh)
  ##[error]The operation was canceled.
• Prototype tests on Linux / unittests-prototype (3.8, linux.g5.4xlarge.nvidia.gpu, cuda, 11.8) / linux-job (gh)
  RuntimeError: Command docker exec -t 7c7aa756140bd835f68f4f5f76d09736a02af5f2661798336a752a22c6317779 /exec failed with exit code 1
• Tests / unittests-linux (3.8, linux.g5.4xlarge.nvidia.gpu, cuda, 11.8) / linux-job (gh)
  RuntimeError: Command docker exec -t a5452a2a15db02814f94ed59dfc4e9ebee5f15dae83bc01dd4e618b7392e7370 /exec failed with exit code 1

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[NicolasHug]

Thanks a lot @rizavelioglu ! Should we do the same change for KeyPointRCNN?

[rizavelioglu]

Thank you @NicolasHug!

Yes, that makes sense. I have just fixed it, too