New review comment by ericonr on void-packages repository

https://github.com/void-linux/void-packages/pull/28582#discussion_r572125238

Comment:
Maybe leave a comment about it being a hack? The issue with these hooks is that some of them we'd like to run only once, and others we'd like to run despite it having been run already, so a general `.pre-pkg-hook-*` mechanism isn't enough :/

Still, I thought `ln -sf` avoid issues with creating symlinks inside symlinks.