Revert "chore: fix typo in FileIO Schemes (apache#653)"

This reverts commit cda4a0c.

Author: chenzl25

crates/iceberg/src/io/file_io.rs

@@ -40,7 +40,7 @@ use crate::{Error, ErrorKind, Result};
 /// | Local file system  | `storage-fs`      | `file`     |
 /// | Memory             | `storage-memory`  | `memory`   |
 /// | S3                 | `storage-s3`      | `s3`, `s3a`|
-/// | GCS                | `storage-gcs`     | `gcs`       |
+/// | GCS                | `storage-gcs`     | `gs`       |
 #[derive(Clone, Debug)]
 pub struct FileIO {
     builder: FileIOBuilder,

crates/iceberg/src/io/storage.rs

@@ -171,7 +171,7 @@ impl Storage {
             "memory" => Ok(Scheme::Memory),
             "file" | "" => Ok(Scheme::Fs),
             "s3" | "s3a" => Ok(Scheme::S3),
-            "gcs" => Ok(Scheme::Gcs),
+            "gs" => Ok(Scheme::Gcs),
             s => Ok(s.parse::<Scheme>()?),
         }
     }