Missing attributes for add translation local task

When adding a translation to a node (and probably other entities), the secondary local tasks show the existing languages, and the one being added. The link for the one being added does not have the 'xml:lang' attribute, nor the 'language-link' class like the others.

I imagine this is pretty obscure... but I use those in my theme to style each tab differently for each language. So the one for the language being added lacks my styling tweaks because of this inconsistency.

Patch to follow :-)