Fix implode docblock to accept callable as parameter (laravel#46869)

Co-authored-by: Finn Paes <[email protected]>

src/Illuminate/Collections/Enumerable.php

@@ -549,7 +549,7 @@ public function hasAny($key);
     /**
      * Concatenate values of a given key as a string.
      *
-     * @param  string  $value
+     * @param  callable|string  $value
      * @param  string|null  $glue
      * @return string
      */