New comment by Chocimier on void-packages repository

https://github.com/void-linux/void-packages/pull/24357#issuecomment-687563103

Comment:
> Can this be added to the Manual too? Don't really care on the exact wording but something along the lines of:
> 
> > We are in the process of transitioning away from noarch. Please no longer use noarch for new packages.

Changes to manual from this PR could be merged first as sign of decision taken.