The "Add links" function enables to join a Wikipedia page from the Commons page, but not in the opposite direction: the dialog doesn't enable to insert "commons" or "c" instead the Wikipedia language code.

"Add links" function doesn't enable to join a Wikipedia page or a Commons page with the existing Wikidata item, using the Wikidata title. The dialog doesn't enable to insert "wikidata" or "d" instead the Wikipedia language code.