New review comment by ahesford on void-packages repository

https://github.com/void-linux/void-packages/pull/26369#discussion_r523466811

Comment:
This doesn't do what you think; the working directory for `post_install` is `${wrksrc}` or, if defined, `${build_wrksrc}`; you are removing `usr/share/doc` from the build tree (which probabaly doesn't exist anyway), not the package destination.