added a large amount of missing documentation

extensions/authclient/widgets/Choice.php

@@ -72,6 +72,7 @@ class Choice extends Widget
 	public $clientIdGetParamName = 'authclient';
 	/**
 	 * @var array the HTML attributes that should be rendered in the div HTML tag representing the container element.
+	 * See [[\yii\helpers\Html::renderTagAttributes()]] for details on how attributes are being rendered.
 	 */
 	public $options = [
 		'class' => 'auth-clients'