Add ancestor iterator to lib.rs (#10813)

Co-authored-by: Carl <carl@solana.com>

ledger/src/lib.rs

@@ -2,6 +2,7 @@ pub mod bank_forks_utils;
 pub mod block_error;
 #[macro_use]
 pub mod blockstore;
+pub mod ancestor_iterator;
 pub mod blockstore_db;
 pub mod blockstore_meta;
 pub mod blockstore_processor;