The options.expires parameter can either be a Date or null.
Change-Id: I22ab2d518f6bb29dcf852115ec26d864647dc60f
* @param {string|null} value Value of cookie. If `value` is `null` then this method will
* instead remove a cookie by name of `key`.
* @param {Object|Date} [options] Options object, or expiry date
- * @param {Date|boolean} [options.expires=wgCookieExpiration] The expiry date of the cookie.
+ * @param {Date|null} [options.expires=wgCookieExpiration] The expiry date of the cookie.
*
* Default cookie expiration is based on `wgCookieExpiration`. If `wgCookieExpiration` is
* 0, a session cookie is set (expires when the browser is closed). For non-zero values of