Update Docblock class

includes/woopay/class-woopay-session.php

@@ -528,7 +528,7 @@ public static function get_init_session_request( $order_id = null, $key = null,
 	/**
 	 * Recursively map an array.
 	 *
-	 * @param function $callback The sanitize_text_field function.
+	 * @param callable $callback The sanitize_text_field function.
 	 * @param array    $array    The nested array.
 	 *
 	 * @return array A new appearance array.