Just a thought, I think it would also help if the link lead to the sitelinks section and not to the top of the page.

It is easy to just add [[…]] around the $2, but for some reason that breaks the wikitext parsing in JavaScript:

"mediawiki.jqueryMsg: wikibase-linkitem-alreadylinked: Parse error at position 115 in input: The page you wanted to link with is already attached to an [$1 item] on the central data repository which links to [[$2]] on this site. Items can only have one page per site attached. Please choose a different page to link with."

Change 511922 had a related patch set uploaded (by Matěj Suchánek; owner: Matěj Suchánek):
[mediawiki/extensions/Wikibase@master] Make wikibase-linkitem-alreadylinked link directly to the article that is already linked

https://gerrit.wikimedia.org/r/511922

that breaks the wikitext parsing in JavaScript

Couldn't reproduce that anymore...

Change 511922 merged by jenkins-bot:
[mediawiki/extensions/Wikibase@master] Make wikibase-linkitem-alreadylinked link directly to the article that is already linked

https://gerrit.wikimedia.org/r/511922