Add blank line before note-render selectors

Improve readability and maintain consistent CSS formatting conventions in typography.css

Author: placek

frontend/styles/typography.css

@@ -184,6 +184,7 @@ n, s, m {
   text-align: left;
   text-shadow: none;
 }
+
 .note-render h1,
 .note-render h2,
 .note-render h3,