This command uses a Hilbert transform to rotate the phase of each selected Sound by 90 degrees.
A 180 degree rotation will invert the waveform.
The resulting new Sound(s) will appear selected in the list of objects.
Parts of code adapted from He and Dellwo (2016) Interspeech.
https://www.isca-archive.org/interspeech_2016/he16_interspeech.html