Steps to reproduce:
- Reply to a comment in a Structured Discussions thread, using the visual mode
- Add a link to [[Topic:Ush5xp8bvwk69y2l]]. It works for any internal link.
- After you've made it, click that link to open it in another browser tab (e.g., to make sure that you linked the correct discussion).
- See the error message from your web browser about the website Topic:Ush5xp8bvwk69y2l not existing. The link ought to be https://www.mediawiki.org/wiki/Topic:Ush5xp8bvwk69y2l instead of just Topic:Ush5xp8bvwk69y2l.
It looks correct in the editing mode, and the link works correctly after the comment is saved: