How to format a comment when using Notify active webhook action?

I'm hoping someone on the community has successfully done this and can give me some tips!

Objective: Using a trigger, we want to send automated messages to customers that include some text formatting (e.g. line breaks, bullet points, hyperlinked text, bold, italic, etc), and that it is visible as a public comment in the ticket.

What we've tried: We have used the "Email user" trigger action in the past, but this does not send a public comment in the ticket, only an email to the customer. This means the agent can't see it in the ticket (in Events they can see an email notification was sent, but the message itself is not visible in a readable way), and the customer can't see it in the Requests ticket page (https://{help center domain}/requests/{ticket-number}).

Where we're stuck: Using the "Notify active webhook" trigger action, we are able to send a public comment to the ticket, but it must be in JSON format. The blocker is we have not figured out a way to send "formatted" text via JSON and have Zendesk translate it to nicely formatted  text for customers.