[Documentation] Missing setting "Attenuation at ceiling" in documentation

[Ilja van Ipenburg]

Hi,

On the following page:
https://www.fon.hum.uva.nl/praat//manual/Sound__To_Pitch__filtered_ac____.html
or in the docstring in file fon/manual_pitch.cpp an explanation for the setting attenuationAtCeiling as seen here is missing.

I don't know enough about pitch analysis to add it, but hope this issue is helpful.