Fixed #34621 -- Made admin site header render in <div> tag.

This was problematic for screen reader users because they use headings
to navigate. Having two <h1> is confusing, and the one in the header
wasn’t particularly helpful since it’s the same on all pages.

docs/intro/tutorial07.txt

@@ -367,7 +367,7 @@ a section of code like:
 .. code-block:: html+django
 
     {% block branding %}
-    <h1 id="site-name"><a href="{% url 'admin:index' %}">Polls Administration</a></h1>
+    <div id="site-name"><a href="{% url 'admin:index' %}">Polls Administration</a><div>
     {% endblock %}
 
 We use this approach to teach you how to override templates. In an actual

docs/ref/contrib/admin/index.txt

@@ -2848,9 +2848,13 @@ Templates can override or extend base admin templates as described in
 
 .. attribute:: AdminSite.site_header
 
-    The text to put at the top of each admin page, as an ``<h1>`` (a string).
+    The text to put at the top of each admin page, as a ``<div>`` (a string).
     By default, this is "Django administration".
 
+    .. versionchanged:: 5.0
+
+        In older versions, ``site_header`` was using an ``<h1>`` tag.
+
 .. attribute:: AdminSite.site_title
 
     The text to put at the end of each admin page's ``<title>`` (a string). By

docs/releases/5.0.txt

@@ -419,6 +419,11 @@ Miscellaneous
 * :class:`~django.db.models.functions.Now` database function now uses
   ``LOCALTIMESTAMP`` instead of ``CURRENT_TIMESTAMP`` on Oracle.
 
+* :attr:`.AdminSite.site_header` is now rendered in a ``<div>`` tag instead of
+  ``<h1>``. Screen reader users rely on heading elements for navigation within
+  a page. Having two ``<h1>`` elements was confusing and the site header wasn't
+  helpful as it is repeated on all pages.
+
 .. _deprecated-features-5.0:
 
 Features deprecated in 5.0