Fixed handout header

lib/typst/local/handout/0.1.0/header.typ

@@ -44,6 +44,14 @@
     by = text(size: 10pt, [Prepared by #by on #date])
   }
 
+  let sub = ()
+  if (by != none) {
+    sub.push(by)
+  }
+  if (subtitle != none) {
+    sub.push(subtitle)
+  }
+
   // Main title
   align(
     center,
@@ -61,8 +69,7 @@
           // Title
           text(size: 20pt, title),
           // Subtitle
-          if (by != none) { text(size: 10pt, by) },
-          if (subtitle != none) { text(size: 10pt, subtitle) },
+          ..sub,
           line(length: 100%, stroke: 0.2mm),
         ),
       ),