fix: incorrect disc number handling in ape tag writer

Author: AyaseFile

lofty/src/ape/tag/mod.rs

@@ -285,11 +285,11 @@ impl Accessor for ApeTag {
 	}
 
 	fn remove_disk_total(&mut self) {
-		let existing_track_number = self.track();
+		let existing_disk_number = self.disk();
 		self.remove("Disc");
 
-		if let Some(track) = existing_track_number {
-			self.insert(ApeItem::text("Disc", track.to_string()));
+		if let Some(disk) = existing_disk_number {
+			self.insert(ApeItem::text("Disc", disk.to_string()));
 		}
 	}
 
@@ -564,7 +564,7 @@ pub(crate) fn tagitems_into_ape(tag: &Tag) -> impl Iterator<Item = ApeItemRef<'_
 		.chain(create_apeitemref_for_number_pair(
 			tag.get_string(ItemKey::DiscNumber),
 			tag.get_string(ItemKey::DiscTotal),
-			"Disk",
+			"Disc",
 		))
 }