Best way to document Array options in PHPDoc?

This is how I do it instead:

/**
 * Class constructor.
 *
 * @param array $params Array containing the necessary params.
 *    $params = [
 *      'hostname'     => (string) DB hostname. Required.
 *      'databaseName' => (string) DB name. Required.
 *      'username'     => (string) DB username. Required.
 *      'password'     => (string) DB password. Required.
 *      'port'         => (int) DB port. Default: 1433.
 *      'sublevel'     => [
 *          'key' => (\stdClass) Value description.
 *      ]
 *    ]
 */
 public function __construct(array $params){}

Think it's quite clean and easy to understand what $params should be.

I wrote a plugin for phpstorm that allows specifying keys like this:

(basically just a slightly more formalized version of @siannone's format)

/**
 * @param array $arr = [
 *     'fields' => [ // Defines the feilds to be shown by scaffolding
 *         $anyKey => [
 *             'name' => 'sale', // Overrides the field name (default is the array key)
 *             'model' => 'customer', // (optional) Overrides the model if the field is a belongsTo associated value.
 *             'width' => '100px', // Defines the width of the field for paginate views. Examples are "100px" or "auto"
 *             'align' => 'center', // Alignment types for paginate views (left, right, center)
 *             'format' => 'nice', // Formatting options for paginate fields. Options include ('currency','nice','niceShort','timeAgoInWords' or a valid Date() format)
 *             'title' => 'Sale', // Changes the field name shown in views.
 *             'desc' => 'A deal another person that results in money', // The description shown in edit/create views.
 *             'readonly' => false, // True prevents users from changing the value in edit/create forms.
 *             'type' => 'password', // Defines the input type used by the Form helper
 *             'options' => ['option1', 'option2'], // Defines a list of string options for drop down lists.
 *             'editor' => false, // If set to True will show a WYSIWYG editor for this field.
 *             'default' => '', // The default value for create forms.
 *         ],
 *     ],
 * ]
 */
public static function processForm($arr)
{
    $fieldName = 'sale';
    $arr['fields'][$fieldName][''];
}

It allows to specify @return keys as well:

/**
 * @return array [
 *     'success' => true,
 *     'formObject' => new Form,
 *     'errors' => [],
 * ]
 */
public static function processForm($arr);