Update Pitch documentation

[Digitalone1]

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With the switch to soundtouch the documentation needs to be updated with the new features.

Besides some controls are hard to translate. @wwmm can you link the original documentation? Thanks.

[wwmm]

can you link the original documentation?

So far that is what I found

https://www.surina.net/soundtouch/ https://www.surina.net/article/time-and-pitch-scaling.html https://codeberg.org/soundtouch/soundtouch/src/branch/master/source/SoundStretch/main.cpp

The library header also has some explanation /usr/include/soundtouch/SoundTouch.h