* Properties:
* - #default_value: A valid URL string.
* - #size: The size of the input element in characters.
+ * - #pattern: A string for the native HTML5 pattern attribute.
*
* Usage example:
* @code
* '#type' => 'url',
* '#title' => $this->t('Home Page'),
* '#size' => 30,
+ * '#pattern' => '*.example.com',
* ...
* );
* @endcode