We are embedding ikiwiki in a frame. When clicking around within the wiki, it makes sense to stay in the frame. But when clicking on an external link, it makes more sense to open the link in a new window (new tab). Especially if the link is to the containing website, otherwise we end up with some kind site-within-the-site situation.

Is there an equivalent to `<a href="blah" target="_blank">...</a>` for Markdown links, or a way to enforce it?

(I am aware from [[CSS_classes_for_links]] and [[rel__61__nofollow_on_external_links]] that this may not be possible because rules for external links are tricky/impossible. If it's possible to do it manually, that would be "good enough".)
