Use documentURI/URL instead of location.href.

document.location is null after the document is detached from its parent window (e.g. after we navigate to a different page in the same hidden browser)

I'm not sure if there's a good reason to include document.URL. I included it just in case.

Addresses https://forums.zotero.org/discussion/34211/save-multiple-items-from-wiley/ and probably quite a few of other translation errors