Use tix shortcode instead of link

Author: gallimorej

content/events/2025-washington-dc/registration.md

@@ -1,11 +1,11 @@
 +++
 Title = "Registration"
 Type = "event"
-Description = "Registration for devopsdays washington-dc 2025"
+Description = "Registration for DevOpsDays DC 2025"
 +++
 
 <div style="width:100%; text-align:left;">
 
-Embed registration iframe/link/etc.
-</div></div>
-</div>
+{{< tix city="washington-dc" year="2025" >}}
+
+</div>