Merge pull request #5859 from braze-inc/BD-2301

BD-2301: Minor tweaks to API endpoint parameters

_docs/_api/endpoints/messaging/send_messages/post_send_triggered_campaigns.md

@@ -68,12 +68,12 @@ Authorization: Bearer YOUR-REST-API-KEY
 |`trigger_properties`| Optional | Object | See [trigger properties]({{site.baseurl}}/api/objects_filters/trigger_properties_object/). Personalization key-value pairs that will apply to all users in this request. |
 |`broadcast`| Optional | Boolean | You must set `broadcast` to true when sending a message to an entire segment that a campaign or Canvas targets. This parameter defaults to false (as of August 31, 2017). <br><br> If `broadcast` is set to true, a `recipients` list cannot be included. However, use caution when setting `broadcast: true`, as unintentionally setting this flag may cause you to send your message to a larger than expected audience. |
 |`audience`| Optional | Connected audience object| See [connected audience]({{site.baseurl}}/api/objects_filters/connected_audience/). |
-|`recipients`| Optional | Array | See [recipients object]({{site.baseurl}}/api/objects_filters/recipient_object/). If not provided and `broadcast` is set to true, the message will send to the entire segment targeted by the campaign. |
+|`recipients`| Optional | Array | See [recipients object]({{site.baseurl}}/api/objects_filters/recipient_object/).<br><br>If `send_to_existing_only` is `false`, an attribute object must be included.<br><br>If `recipients` is not provided and `broadcast` is set to true, the message will send to the entire segment targeted by the campaign. |
 {: .reset-td-br-1 .reset-td-br-2 .reset-td-br-3  .reset-td-br-4}
 
-The recipients array may contain up to 50 objects, with each object containing a single `external_user_id` string and `trigger_properties` object.
-
-When `send_to_existing_only` is `true`, Braze will only send the message to existing users. However, this flag can't be used with user aliases. When `send_to_existing_only` is `false` and a user with the given `id` does not exist, Braze will create a user with the `id` and attributes before sending the message.
+- The recipients array may contain up to 50 objects, with each object containing a single `external_user_id` string and `trigger_properties` object.
+- When `send_to_existing_only` is `true`, Braze will only send the message to existing users. However, this flag can't be used with user aliases. 
+- When `send_to_existing_only` is `false`, an attribute must be included. Braze will create a user with the `id` and attributes before sending the message.
 
 {% alert important %}
 A user's subscription group status can be updated via the inclusion of a `subscription_groups` parameter within the `attributes` object. This is currently in early access. Contact your Braze customer success manager if you're interested in participating in the early access. More details can be found in the [User attributes object]({{site.baseurl}}/api/objects_filters/user_attributes_object).