fix: invalid HTML: <h1> Nested Inside <span> (#968) (#1000)

Author: Yuliaborzhak

src/unfold/templates/unfold/helpers/site_icon.html

@@ -16,6 +16,6 @@
     </a>
 {% endif %}
 
-<span class="text-font-important-light tracking-tight dark:text-font-important-dark xl:text-base">
+<div class="text-font-important-light tracking-tight dark:text-font-important-dark xl:text-base">
     {{ branding }}
-</span>
+</div>