User ID: Add "multiple storage types" option

dev-docs/modules/userId.md

@@ -88,8 +88,8 @@ The table below has the options that are common across ID systems. See the secti
 | name | Required | String | May be any of the following values: {% for page in userid_pages -%}{% if count == 1 %}{{ name_string | append: ", " -}}{% endif %}{% assign count = 1 %}`"{{ name_string | append: name_string -}}{{ name_string | append: page.useridmodule -}}"`{% endfor %} | `"unifiedId"` |
 | params | Based on User ID sub-module | Object | | |
 | bidders | Optional | Array of Strings | An array of bidder codes to which this user ID may be sent. | `['bidderA', 'bidderB']` |
-| storage | Optional | Object | The publisher can specify some kind of local storage in which to store the results of the call to get the user ID. This can be either cookie or HTML5 storage. This is not needed when `value` is specified or the ID system is managing its own storage | |
-| storage.type | Required | String | Must be either `"cookie"` or `"html5"`. This is where the results of the user ID will be stored. | `"cookie"` |
+| storage | Optional | Object | The publisher can specify some kind of local storage in which to store the results of the call to get the user ID. This can be either cookie, HTML5 storage or both. This is not needed when `value` is specified or the ID system is managing its own storage | |
+| storage.type | Required | String | Must be either `"cookie"` or `"html5"` or both `"cookie&html5"`. This is where the results of the user ID will be stored. | `"cookie"` |
 | storage.name | Required | String | The name of the cookie or html5 local storage where the user ID will be stored. | `"_unifiedId"` |
 | storage.expires | Strongly Recommended | Integer | How long (in days) the user ID information will be stored. If this parameter isn't specified, session cookies are used in cookie-mode, and local storage mode will create new IDs on every page. | `365` |
 | storage.refreshInSeconds | Optional | Integer | The amount of time (in seconds) the user ID should be cached in storage before calling the provider again to retrieve a potentially updated value for their user ID. If set, this value should equate to a time period less than the number of days defined in `storage.expires`. By default the ID will not be refreshed until it expires. | `30` |