Minor cleanups

Pulling out some of the smaller changes that aren't related to the manga controller changes in #7244

app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadManager.kt

@@ -102,8 +102,9 @@ class DownloadManager(
         downloader.clearQueue(isNotification)
     }
 
-    fun startDownloadNow(chapter: Chapter) {
-        val download = downloader.queue.find { it.chapter.id == chapter.id } ?: return
+    fun startDownloadNow(chapterId: Long?) {
+        if (chapterId == null) return
+        val download = downloader.queue.find { it.chapter.id == chapterId } ?: return
         val queue = downloader.queue.toMutableList()
         queue.remove(download)
         queue.add(0, download)

app/src/main/java/eu/kanade/tachiyomi/data/download/model/Download.kt

@@ -6,9 +6,12 @@ import eu.kanade.tachiyomi.source.model.Page
 import eu.kanade.tachiyomi.source.online.HttpSource
 import rx.subjects.PublishSubject
 
-class Download(val source: HttpSource, val manga: Manga, val chapter: Chapter) {
-
-    var pages: List<Page>? = null
+data class Download(
+    val source: HttpSource,
+    val manga: Manga,
+    val chapter: Chapter,
+    var pages: List<Page>? = null,
+) {
 
     @Volatile
     @Transient