Link to Fastly DNS config info for apex domains (#8287)

* Link to Fastly DNS config info for apex domains

Per customer feedback, updated the Fastly set up instructions for
DNS configuration settings for development environment to include
link to instructions for setting up A records for apex domains.

* Fix trailing spaces

* Update src/cloud/cdn/configure-fastly.md

Co-authored-by: Bruce Denham <bdenham@adobe.com>

Author: meker12

src/cloud/cdn/configure-fastly.md

@@ -185,6 +185,9 @@ To update your DNS configuration for development:
 
    When the CNAME records are live, Magento provisions certificates and uploads the SSL/TLS certificates.
 
+   {:.bs-callout-info}
+   If you plan to use apex domains (`your-domain.com`) for your Production site, you must configure DNS address records (A records) to point to the Fastly server IP addresses. See [Update DNS configuration with production settings]({{ site.baseurl }}/cloud/live/site-launch-checklist.html#dns).
+
 1. Add ACME challenge CNAME records for domain validation and pre-provisioning of Production SSL/TLS certificates, for example:
 
    | Domain or Subdomain  | CNAME