New review comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/23515#discussion_r453153888

Comment:
I see, that makes sense. Do you think we could add some of this info to the manual, as well? I think it would help a lot. Also with information about the helper and how to best use it - so always add numpy to `hostmakedepends`, while `makedepends` should only be touched by the helper, if I understand correctly.