Fix dangling link to branch I deleted after merge. Link instead to merged commits...

[ikiwiki] / doc / bugs / debwiki_shortcut_creates_buggy_URLs_to_subpages.mdwn

E.g. [[!debwiki Derivatives/Guidelines]].

Maybe we should use `%S` instead of `%s` in the shortcut definition?

> seems reasonable, [[done]] --[[smcv]]