refactor: Update Duplicateable interface.

src/Contract/Operation/Duplicateable.php

@@ -19,9 +19,23 @@ interface Duplicateable
 {
     /**
      * Find duplicated values from the collection.
+     * The operation has 2 optional parameters that allow you to customize precisely
+     * how values are accessed and compared to each other.
+     *
+     * The first parameter is the comparator. This is a curried function which takes
+     * first the left part, then the right part and then returns a boolean.
+     *
+     * The second parameter is the accessor. This binary function takes the value and the key
+     * of the current iterated value and then return the value to compare.
+     * This is useful when you want to compare objects.
      *
      * @see https://loophp-collection.readthedocs.io/en/stable/pages/api.html#duplicate
      *
+     * @template U
+     *
+     * @param null|callable(U): (Closure(U): bool) $comparatorCallback
+     * @param null|callable(T, TKey): U $accessorCallback
+     *
      * @return Collection<TKey, T>
      */
     public function duplicate(?callable $comparatorCallback = null, ?callable $accessorCallback = null): Collection;