Site: The link https://iceberg.apache.org/concepts/catalog/ doesn't exist anymore. (#2683)

Author: jbonofre

site/content/in-dev/unreleased/_index.md

@@ -65,7 +65,7 @@ query engine to manage and organize tables. The catalog forms the first architec
 - Performing atomic operations so that you can update the current metadata pointer for a table to the metadata pointer of a new version of
   the table.
 
-To learn more about Iceberg catalogs, see the [Apache Iceberg™ documentation](https://iceberg.apache.org/concepts/catalog/).
+To learn more about Iceberg REST catalogs, see the [Apache Iceberg™ REST catalog specification](https://iceberg.apache.org/rest-catalog-spec/).
 
 #### Catalog types