Fix numbr of files, total additions, and deletions (#11614)

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

modules/repofiles/diff_test.go

@@ -108,6 +108,7 @@ func TestGetDiffPreview(t *testing.T) {
 		},
 		IsIncomplete: false,
 	}
+	expectedDiff.NumFiles = len(expectedDiff.Files)
 
 	t.Run("with given branch", func(t *testing.T) {
 		diff, err := GetDiffPreview(ctx.Repo.Repository, branch, treePath, content)