There is an updated pull request by paper42 against master on the void-packages repository

https://github.com/paper42/void-packages remove-xournal
https://github.com/void-linux/void-packages/pull/38440

xournal: remove package
gtk2, dead upstream, xournalpp is a modern replacement

A patch file from https://github.com/void-linux/void-packages/pull/38440.patch is attached