added auto participant creation for notes

src/diagram.typ

@@ -130,6 +130,21 @@
       } else if elmt.side == "right" {
         linked.push("]")
       }
+
+      let pars = none
+      if type(elmt.pos) == str {
+        pars = (elmt.pos,)
+      } else if type(elmt.pos) == array {
+        pars = elmt.pos
+      }
+      if pars != none {
+        for par in pars {
+          if not participant._exists(participants, par) {
+            participants.push(_par(par).first())
+          }
+        }
+      }
+
       last-note = (
         elmt: elmt,
         i: i