unified header_title template values across dashboard applet destination pages; styled &/ added applet titles across all applets

src/templates/apps/dashboard/_partials/_applet-my-notes.html

@@ -2,7 +2,7 @@
     id="id_applet_my_notes"
     style="--applet-cols: {{ entry.applet.grid_cols }}; --applet-rows: {{ entry.applet.grid_rows }};"
 >
-    <a href="{% url 'my_notes' user.id %}" class="my-notes-main">My notes:</a>
+    <h2><a href="{% url 'my_notes' user.id %}" class="my-notes-main">My notes</a></h2>
     <div class="my-notes-container">
         <ul>
             {% for note in recent_notes %}