scss: set smaller font size for track lists

- Sets a smaller font size for track lists in post publishing lives.
  This suppose to use pandoc as markup converter, and to add a `<div>`
  around the list to specify the `.tracklist` class.

Co-Authored-by: iGor milhit <igor@milhit.ch>

assets/scss/_lists.scss

@@ -106,6 +106,10 @@ details[open] > ul {
   }
 }
 
+.tracklist {
+  font-size: smaller;
+}
+
 .list-footer {
   padding-left: .5em;
 }