Right now we do label prefetching in various places, but we can't for entities that are referred to in revision comments as these are only known by the time the revision comments get parsed by Linker::formatLinksInComment. Investigate on whether there's a way to do that.

One possible, but not very nice, solution would be to build a function like Linker::formatLinksInComment that scraps entity ids from comments and aggregates those for prefetching (before the actual parsing and entity loading happens).