refactor: remove legacy snapshot expiration implementation and update README example

Author: ForeverAngry

README.md

@@ -67,7 +67,7 @@ It provides an Iceberg integration for the [Datafusion](https://arrow.apache.org
 
 ## Example
 
-Check out the [datafusion examples](datafusion_iceberg/examples) and [maintenance examples](iceberg-rust/examples/).
+Check out the [datafusion examples](datafusion_iceberg/examples).
 
 ### Basic Table Operations
 

iceberg-rust/src/lib.rs

@@ -46,13 +46,13 @@
 //!     .await?;
 //!
 //! // Expire old snapshots for maintenance
-//! let result = table.expire_snapshots()
+//! let expired_snapshot_ids = table.expire_snapshots()
 //!     .expire_older_than(chrono::Utc::now().timestamp_millis() - 30 * 24 * 60 * 60 * 1000)
 //!     .retain_last(10)
 //!     .execute()
 //!     .await?;
 //!     
-//! println!("Expired {} snapshots", result.expired_snapshot_ids.len());
+//! println!("Expired {} snapshots", expired_snapshot_ids.len());
 //! # Ok(())
 //! # }
 //! ```