[12.x] Fix PHPDoc for Arr::sole method (laravel#56096)

* Fix PHPDoc for Arr::sole method

* Update src/Illuminate/Collections/Arr.php

Co-authored-by: Sebastian Hädrich <[email protected]>

---------

Co-authored-by: Taylor Otwell <[email protected]>
Co-authored-by: Sebastian Hädrich <[email protected]>

Author: 3 people

src/Illuminate/Collections/Arr.php

@@ -948,10 +948,10 @@ public static function shuffle($array)
     }
 
     /**
-     * Get the first item in the collection, but only if exactly one item exists. Otherwise, throw an exception.
+     * Get the first item in the array, but only if exactly one item exists. Otherwise, throw an exception.
      *
      * @param  array  $array
-     * @param  callable  $callback
+     * @param  callable(mixed, array-key): array|null  $callback
      *
      * @throws \Illuminate\Support\ItemNotFoundException
      * @throws \Illuminate\Support\MultipleItemsFoundException