destroy_all_in_batches is off by default for newly generated Rails apps.

Following up rails#42673 (comment)

Author: robertomiranda

activerecord/CHANGELOG.md

@@ -27,9 +27,6 @@
     config.active_record.destroy_all_in_batches = true
     ```
 
-    The option is on by default for newly generated Rails apps. Can be set in
-    an initializer to prevent differences across environments.
-
     *Genadi Samokovarov*, *Roberto Miranda*
 
 *   Adds support for `if_not_exists` to `add_foreign_key` and `if_exists` to `remove_foreign_key`.