No, no word from the developper. I commented on his website too :
https://julienappert.com/realisations/plugin-link-to-post
but no response. And I couldn’t find an alternative plug-in. For now, I am using the standard “Link” button in WordPress. Thanks to the WordPress developers, one of the features provided by the Link to Post plug-in was recently built into the core. This new “Link” feature is relatively hidden (or at least not very obvious), so see screenshot :
https://wpmodspullzone.system0.netdna-cdn.com/wp-content/uploads/2011/03/Screen-shot-2011-03-17-at-10.14.49-AM.png
Unfortunately, you can’t link to tags using this built-in feature ; and because it’s core, you can’t fiddle with the code.