Rename offline mode to downloaded only

app/src/main/java/eu/kanade/tachiyomi/ui/manga/chapter/ChaptersController.kt

@@ -155,7 +155,7 @@ class ChaptersController : NucleusController<ChaptersControllerBinding, Chapters
         menuFilterRead.isChecked = presenter.onlyRead()
         menuFilterUnread.isChecked = presenter.onlyUnread()
         menuFilterDownloaded.isChecked = presenter.onlyDownloaded()
-        menuFilterDownloaded.isEnabled = !presenter.isOfflineMode()
+        menuFilterDownloaded.isEnabled = !presenter.forceDownloaded()
         menuFilterBookmarked.isChecked = presenter.onlyBookmarked()
 
         val filterSet = presenter.onlyRead() || presenter.onlyUnread() || presenter.onlyDownloaded() || presenter.onlyBookmarked()

app/src/main/java/eu/kanade/tachiyomi/ui/manga/chapter/ChaptersPresenter.kt

@@ -367,17 +367,17 @@ class ChaptersPresenter(
     }
 
     /**
-     * Whether offline mode is enabled (i.e. force only downloaded content).
+     * Whether downloaded only mode is enabled.
      */
-    fun isOfflineMode(): Boolean {
-        return preferences.offlineMode().get()
+    fun forceDownloaded(): Boolean {
+        return preferences.downloadedOnly().get()
     }
 
     /**
      * Whether the display only downloaded filter is enabled.
      */
     fun onlyDownloaded(): Boolean {
-        return isOfflineMode() || manga.downloadedFilter == Manga.SHOW_DOWNLOADED
+        return forceDownloaded() || manga.downloadedFilter == Manga.SHOW_DOWNLOADED
     }
 
     /**