API: Add note about leaking blobs on delete

We can address this later, it's not really a big deal.

api/graph/schema.resolvers.go

@@ -208,6 +208,7 @@ func (r *mutationResolver) Delete(ctx context.Context, id string) (*model.Paste,
 	var paste model.Paste
 
 	if err := database.WithTx(ctx, nil, func(tx *sql.Tx) error {
+		// TODO: This can leak blobs
 		row := tx.QueryRowContext(ctx, `
 			DELETE FROM paste
 			WHERE sha = $1 AND user_id = $2