This does not matter much to me, just wanted to notify you.
The link [[:sv:whatever]] is not well-defined. It is a link to Swedish version of the mw-project. [[w:sv:whatever]] is a link to the Swedish version of Wikipedia. I never use the first version except when linking to language specific versions of the same project, even if the form works on some (mw) projects.
You should never break the user expectations, but some devs are not very good at following user expectations. The page Special:Interwiki is a study in how to break them! Take a look at the definitions for Wiktionary and Wikiversity for example. =)
But other than that; not sure why I but the additional link inside the marker.