docs: fix broken catalog example links (#18765)

## Which issue does this PR close?

Related to #18142 and
#18743

## Rationale for this change

The catalog examples were moved under
`datafusion-examples/examples/data_io/`, but the doc comments and user
guide
still point to the old paths. This leaves readers with 404s when they
try to follow the examples, so the links need
  to be corrected.

## What changes are included in this PR?

Correct the catalog example links so they point to the examples/data_io
directory.

Author: nlimpid

datafusion/catalog/src/async.rs

@@ -193,7 +193,7 @@ impl CatalogProviderList for ResolvedCatalogProviderList {
 ///
 /// See the [remote_catalog.rs] for an end to end example
 ///
-/// [remote_catalog.rs]: https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/remote_catalog.rs
+/// [remote_catalog.rs]: https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/data_io/remote_catalog.rs
 #[async_trait]
 pub trait AsyncSchemaProvider: Send + Sync {
     /// Lookup a table in the schema provider

datafusion/catalog/src/catalog.rs

@@ -61,7 +61,7 @@ use datafusion_common::Result;
 /// schemas and tables exist.
 ///
 /// [Delta Lake]: https://delta.io/
-/// [`remote_catalog`]: https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/remote_catalog.rs
+/// [`remote_catalog`]: https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/data_io/remote_catalog.rs
 ///
 /// The [`CatalogProvider`] can support this use case, but it takes some care.
 /// The planning APIs in DataFusion are not `async` and thus network IO can not
@@ -100,7 +100,7 @@ use datafusion_common::Result;
 ///
 /// [`datafusion-cli`]: https://datafusion.apache.org/user-guide/cli/index.html
 /// [`DynamicFileCatalogProvider`]: https://github.com/apache/datafusion/blob/31b9b48b08592b7d293f46e75707aad7dadd7cbc/datafusion-cli/src/catalog.rs#L75
-/// [`catalog.rs`]: https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/catalog.rs
+/// [`catalog.rs`]: https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/data_io/catalog.rs
 /// [delta-rs]: https://github.com/delta-io/delta-rs
 /// [`UnityCatalogProvider`]: https://github.com/delta-io/delta-rs/blob/951436ecec476ce65b5ed3b58b50fb0846ca7b91/crates/deltalake-core/src/data_catalog/unity/datafusion.rs#L111-L123
 ///

docs/source/library-user-guide/catalogs.md

@@ -19,7 +19,7 @@
 
 # Catalogs, Schemas, and Tables
 
-This section describes how to create and manage catalogs, schemas, and tables in DataFusion. For those wanting to dive into the code quickly please see the [example](https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/catalog.rs).
+This section describes how to create and manage catalogs, schemas, and tables in DataFusion. For those wanting to dive into the code quickly please see the [example](https://github.com/apache/datafusion/blob/main/datafusion-examples/examples/data_io/catalog.rs).
 
 ## General Concepts