The ((User Wikidata)) template shows that the user is also a user of Wikidata. It should not be substed. It takes one optional parameter, the name of the user on Wikidata (only if the user has a different name on Wikidata). "a page" will never be a redlink due to the nature of cross-project linking, so please check your work by previewing and following the link.
((User Wikidata|name on Wikidata))
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((User Wikidata))
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((User Wikidata|Example))
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