index: replace custom EachByPackResult datatype

internal/repository/index/index.go

@@ -228,11 +228,6 @@ func (idx *Index) Values() iter.Seq[restic.PackedBlob] {
 	}
 }
 
-type EachByPackResult struct {
-	PackID restic.ID
-	Blobs  restic.Blobs
-}
-
 // EachByPack returns a channel that yields all blobs known to the index
 // grouped by packID but ignoring blobs with a packID in packPlacklist for
 // finalized indexes.
@@ -240,10 +235,10 @@ type EachByPackResult struct {
 // from the finalized index which have been re-read into a non-finalized index.
 // When the  context is cancelled, the background goroutine
 // terminates. This blocks any modification of the index.
-func (idx *Index) EachByPack(ctx context.Context, packBlacklist restic.IDSet) <-chan EachByPackResult {
+func (idx *Index) EachByPack(ctx context.Context, packBlacklist restic.IDSet) <-chan restic.PackBlobs {
 	idx.m.RLock()
 
-	ch := make(chan EachByPackResult)
+	ch := make(chan restic.PackBlobs)
 
 	go func() {
 		defer idx.m.RUnlock()
@@ -264,7 +259,7 @@ func (idx *Index) EachByPack(ctx context.Context, packBlacklist restic.IDSet) <-
 		}
 
 		for packID, packByType := range byPack {
-			var result EachByPackResult
+			var result restic.PackBlobs
 			result.PackID = packID
 			for typ, p := range packByType {
 				for _, e := range p {