replace overly-optimistic messages when no citations found

[VladimirAlexiev]

From the Cita menu of an item that has no citations, and none in Wikidata:

• Sync with Wikidata: "Citations fetched. All up to date"
• Auto link citations with Zotero items: "Automatic linking done"

These messages are overly-optimistic and thus misleading. For this case, replace them :

• with "No citations found"
• (better) with a specific number of processed citations/links, and show "0" in red or as "none"

[Dominic-DallOsto]

Sorry for the slow response. I think this makes sense to add more detailed feedback for users.

I'll try and get around to this soon.