Implement fsync for delete operations in local.rs

[kevinjqliu]

WHy doesn't fsync apply to standalone deletes (if we don't fsync isn't there some chance that a deleted file will get "undeleted" on crash)?

it should! but it doesnt right now, the documented mentions only write-like operations and not deletes

arrow-rs-object-store/src/local.rs

Lines 310 to 316 in c9db3e2

	/// When enabled, [`LocalFileSystem`] calls [`File::sync_all`] on written files and fsyncs
	/// the affected parent directories before a write operation
	/// ([`put_opts`](ObjectStore::put_opts), [`copy_opts`](ObjectStore::copy_opts),
	/// [`rename_opts`](ObjectStore::rename_opts), and multipart upload completion) returns
	/// success. This guarantees that both the file contents and the directory entries pointing
	/// to them are durable on stable storage, matching the implicit durability contract of
	/// remote object stores such as S3 or GCS.

Let's do a follow up to make standalone delete / delete_stream crash-durable

Originally posted by @kevinjqliu in #758 (comment)

[kevinjqliu]

• update the fsync documentation to include delete.
• remove this inline comment https://github.com/apache/arrow-rs-object-store/pull/758/changes#diff-8b15b84c016d140bf2a5c14a87cb490efd01cad00d0ac6e746103e9fc8681a39R516-R518