[docs] Strange default window argument wording in MelSpectrogram

[vadimkantorov]

https://pytorch.org/audio/transforms.html?highlight=melspectrogram#torchaudio.transforms.MelSpectrogram:

torchaudio.transforms.MelSpectrogram(sample_rate=16000, n_fft=400, win_length=None, hop_length=None, f_min=0.0, f_max=None, pad=0, n_mels=128, window_fn=<built-in method hann_window of type object>, wkwargs=None)

Very strange wording: <built-in method hann_window of type object>

If it's for torch.hann_window, having it verbatim is clearer

[Mistobaan]

I think this is an artifact from the auto-doc-conversion script. The field documentation is explicit:

window_fn (Callable[[..], torch.Tensor]) – A function to create a window tensor that is applied/multiplied to each frame/window. (Default: torch.hann_window)

Also not sure about having the wkwargs inside the signature of those methods. is it that a requirement of the JIT? if the function needs parameters it should use a partial function. The Class should not be responsible of composing the function.