refactored sequences, sync and gaps

src/sync.typ

@@ -1,27 +1,10 @@
 #import "sequence.typ"
+#import "core/draw/sync.typ"
 
 #let _sync(elmts) = {
   return ((
     type: "sync",
+    draw: sync.render,
     elmts: elmts
   ),)
 }
-
-#let render(pars-i, x-pos, participants, elmt, y, lifelines) = {
-  let draw-seq = sequence.render.with(pars-i, x-pos, participants)
-
-  let shapes = ()
-
-  let end-y = y
-
-  for e in elmt.elmts {
-    let yi
-    let shps
-    (yi, lifelines, shps) = draw-seq(e, y, lifelines)
-    shapes += shps
-    end-y = calc.min(end-y, yi)
-  }
-
-  let r = (end-y, lifelines, shapes)
-  return r
-}