1. 862573eab added references to fileRenaming.ftl strings but didn't
add a <link> to it, so document.l10n.formatMessages() returned
nothing. It fell back to Zotero.getString(), which threw an error
due to a missing string in en-US. We didn't catch that, so the entire
search process aborted every time.
2. message.attributes is an optional array of { name, value } objects,
not an object itself, so we were never successfully adding FTL .title
and .label attributes to the parsed strings.
This fixes the 862573eab regression, and makes search match FTL
attributes as it was always intended to.
Fixes#5947
80ca898a74
