Handle redirected sitelinks better

[wetneb]

It is possible to affect a wikipedia redirect to an item (although it's a bit of a hack).
If the redirect goes to a subsection of another page, then the two wikidata items represent different things! So our algorithm is incorrect in this case.
https://en.wikipedia.org/wiki/Registry_of_Open_Access_Repositories_Mandatory_Archiving_Policies
should reconcile to https://www.wikidata.org/wiki/Q7277308, not to https://www.wikidata.org/wiki/Q861552