Update the documentation

Author: tabito-hara

website/docs/r/pinpointsmsvoicev2_phone_number.html.markdown

@@ -37,7 +37,7 @@ This resource supports the following arguments:
 * `opt_out_list_name` - (Optional) The name of the opt-out list to associate with the phone number.
 * `registration_id` - (Optional) Use this field to attach your phone number for an external registration process.
 * `self_managed_opt_outs_enabled` - (Optional) When set to `false` an end recipient sends a message that begins with HELP or STOP to one of your dedicated numbers, AWS End User Messaging SMS and Voice automatically replies with a customizable message and adds the end recipient to the opt-out list. When set to true you’re responsible for responding to HELP and STOP requests. You’re also responsible for tracking and honoring opt-out request.
-* `two_way_channel_arn` - (Optional) The Amazon Resource Name (ARN) of the two way channel.
+* `two_way_channel_arn` - (Optional) Configuration for two-way SMS. Specify an ARN to receive incoming SMS messages, or `connect.[region].amazonaws.com` (with `[region]` replaced by the AWS Region of the Amazon Connect instance) to set Amazon Connect as the inbound destination.
 * `two_way_channel_enabled` - (Optional) By default this is set to `false`. When set to `true` you can receive incoming text messages from your end recipients.
 * `two_way_channel_role` - (Optional) IAM Role ARN for a service to assume, to be able to post inbound SMS messages.