title: How to detect a string and replace with a URL in a user-generated message
body: <p>New at Slack programming and, admittedly, it's been a while since I've developed much of anything. </p>
  
  <p>I'm looking for direction on how to automatically convert any ticket # posted by anyone in any channel and convert it to a deep link into our ticketing system. </p>
  
  <p>So, perhaps the original message was something like:</p>
  
  <blockquote>
    <p>"Who is working on Ticket #212373?"</p>
  </blockquote>
  
  <p>I'd like '#212373' to be automatically be converted to a link into our ticketing system. Bonus points if it will then expand with other details/attributes from the ticket in the target system, such as customer name, issue description, current status, etc.</p>
  
  <p>Can anyone give me some direction, perhaps in showing me which API to target, whether it's possible, recommended approach, etc?</p>