Fix empty page results update

CHDataManagement/Extensions/Sequence+Sorted.swift

@@ -35,6 +35,12 @@ extension Collection where Element: Collection, Element.Element: Hashable {
     }
 }
 
+extension Collection where Element: Hashable {
+
+    func asSet() -> Set<Element> {
+        Set(self)
+    }
+}
 
 extension RangeReplaceableCollection where Element: Comparable {
 

CHDataManagement/Generator/Results/GenerationResults.swift

@@ -123,6 +123,11 @@ final class GenerationResults: ObservableObject {
         update { self.warnings = warnings }
         let unsavedOutputFiles = cache.values.map { $0.unsavedOutputFiles.keys }.union()
         update { self.unsavedOutputFiles = unsavedOutputFiles }
+        let emptyPages = cache.values.filter { $0.pageIsEmpty }.map { $0.itemId }.compactMap { id -> LocalizedPageId? in
+            guard case .page(let page) = id.itemType else { return nil }
+            return LocalizedPageId(language: id.language, pageId: page.id)
+            }.asSet()
+        update { self.emptyPages = emptyPages }
         let redirects = cache.values.compactMap { $0.redirect }.reduce(into: [:]) { $0[$1.originalUrl] = $1.newUrl }
         update { self.redirects = redirects }
     }