docs: use long property descriptions if available (#899)

Author: childish-sambino

lib/rest/accounts/v1/authTokenPromotion.ts

@@ -110,19 +110,19 @@ export class AuthTokenPromotionInstance {
   }
 
   /**
-   * The SID of the Account that the secondary Auth Token was created for
+   * The SID of the [Account](https://www.twilio.com/docs/iam/api/account) that the secondary Auth Token was created for.
    */
   accountSid: string;
   /**
-   * The promoted Auth Token
+   * The promoted Auth Token that must be used to authenticate future API requests.
    */
   authToken: string;
   /**
-   * The ISO 8601 formatted date and time in UTC when the resource was created
+   * The date and time in UTC when the resource was created specified in [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) format.
    */
   dateCreated: Date;
   /**
-   * The ISO 8601 formatted date and time in UTC when the resource was last updated
+   * The date and time in GMT when the resource was last updated specified in [ISO 8601](https://en.wikipedia.org/wiki/ISO_8601) format.
    */
   dateUpdated: Date;
   /**

lib/rest/accounts/v1/credential/aws.ts

@@ -269,23 +269,23 @@ export class AwsInstance {
   }
 
   /**
-   * The unique string that identifies the resource
+   * The unique string that we created to identify the AWS resource.
    */
   sid: string;
   /**
-   * The SID of the Account that created the resource
+   * The SID of the [Account](https://www.twilio.com/docs/iam/api/account) that created the AWS resource.
    */
   accountSid: string;
   /**
-   * The string that you assigned to describe the resource
+   * The string that you assigned to describe the resource.
    */
   friendlyName: string;
   /**
-   * The RFC 2822 date and time in GMT when the resource was created
+   * The date and time in GMT when the resource was created specified in [RFC 2822](https://www.ietf.org/rfc/rfc2822.txt) format.
    */
   dateCreated: Date;
   /**
-   * The RFC 2822 date and time in GMT when the resource was last updated
+   * The date and time in GMT when the resource was last updated specified in [RFC 2822](https://www.ietf.org/rfc/rfc2822.txt) format.
    */
   dateUpdated: Date;
   /**