rcon: Add Jack Firth's talk (#309)

* rcon: Add Jack Firth's talk

Also, insert a coffee break after the keynote (assumed to be
one hour long).

Author: jessealama

rcon/2024/index.rkt

@@ -348,11 +348,22 @@ $(document).ready(function () {
 @abstract{
 Stay tuned for an exciting keynote speaker announcement!
 }
+]
+
+  @coffee[@talk-time{Saturday, 10:00am}]
+
+  @lecture[
+#:when
+@talk-time{Saturday, 10:30am}
+#:who
+@speaker[#:url "https://github.com/jackfirth"]{Jack Firth}
+#:what
+@talk{Sorted collections in Rebellion}
 ]
 
   @lecture[
 #:when
-@talk-time{Sunday, 10:30am}
+@talk-time{Sunday, 11:00am}
 #:who
 @speaker[#:person? #f]{A friendly Racketeer}
 #:what