BUG FIX PHP 8

Ho risolto alcuni errori per php8:

in class.options.php Linea 501

da: $ret = call_user_func_array( array( ‘parent’, ‘add’ ), $args );

a: $ret = call_user_func_array([parent::class, ‘add’], $args );

in class.field_type.php Linea 435

da: $target_property = $this->util->apply_filters_ref_array( “process_placeholder_${tag}“, [ ”, $this, &$instance, $layout, $data ], false );

a: $target_property = $this->util->apply_filters_ref_array( “process_placeholder_{$tag}“, [ ”, $this, &$instance, $layout, $data ], false );

in class.utilities.php Linea 545

da: $obj = trim( $obj, $sep );

a: $obj = trim( (string) $obj, $sep );