fix sfw sort with nsfw update

if the last update to an item is nsfw-only, then it would affect the
sfw sorting, even tho it is not relevant, and even if it had ignore-sort
set. now it works properly in that situation

make-pages/Info.hs

@@ -163,7 +163,8 @@ instance HasField "notMine" Info Bool where getField = isJust    . #artist
 instance HasField "latestDate" Info (Bool -> Date) where
   getField info@(Info {date=date₀}) nsfw =
     maximum $ date₀ : mapMaybe relDate (updatesFor nsfw info)
-   where relDate (date, us) = date <$ guard (not $ any #ignoreSort us)
+   where
+    relDate (date, us) = date <$ guard (not $ null us || any #ignoreSort us)
 
 instance HasField "latestYear" Info (Bool -> Int) where
   getField info nsfw = #year $ #latestDate info nsfw