[12.x] Document the optional argument on database transactions (#10321)

* Document the optional argument on database transactions

* Update database.md

---------

Co-authored-by: Taylor Otwell <taylor@laravel.com>

Author: AhmedAlaa4611

database.md

@@ -379,6 +379,20 @@ DB::transaction(function () {
 });
 ```
 
+You may optionally pass a closure to the `transaction` method that will be executed if the transaction fails:
+
+```php
+use Illuminate\Support\Facades\DB;
+
+DB::transaction(function () {
+    DB::update('update users set votes = 1');
+
+    DB::delete('delete from posts');
+}, onFailure: function () {
+    // ...
+});
+```
+
 <a name="handling-deadlocks"></a>
 #### Handling Deadlocks