Replace ModelAdmin history header human readable date

- Snippet header with history appears to be unused, updated anyway
- Update ModelAdmin header with history to use the human readable (more accessible) timesince date, which uses Tippy.js
- Relates to #8565
- Builds on #8697 & #8566

docs/releases/5.1.md

@@ -244,6 +244,25 @@ This will be different to the previous ordering which never intentionally implem
 
 This default ordering is now `["content_type__app_label", "content_type__model", "codename"]`, which can now be customised [](customising_group_views_permissions_order).
 
+### Shared include `wagtailadmin/shared/last_updated.html` is no longer available
+
+The undocumented shared include `wagtailadmin/shared/last_updated.html` is no longer available as it used the legacy Bootstrap tooltips and was not accessible. If you need to achieve a similar output, an element that shows a simple date with a tooltip for the full date, use the `human_readable_date` template tag instead.
+
+**Before**
+
+```html+django
+{% include "wagtailadmin/shared/last_updated.html" with last_updated=my_model.timestamp %}
+```
+
+**After**
+
+```html+django
+{% load wagtailadmin_tags %}
+
+<!-- ... -->
+{% human_readable_date my_model.timestamp %}
+```
+
 ### Tag (Tagit) field usage now relies on data attributes
 
 The `AdminTagWidget` widget has now been migrated to a Stimulus controller, if using this widget in Python, no changes are needed to adopt the new approach.

wagtail/admin/templates/wagtailadmin/shared/last_updated.html

@@ -1,6 +0,0 @@
-{% load i18n wagtailadmin_tags %}
-{% if last_updated %}
-    <span title="{{ last_updated }}" data-wagtail-tooltip="{{ last_updated }}" {% if classname %}class="{{ classname }}"{% endif %}>
-        {% if since_text %}{{ since_text }}{% endif %} {% timesince_last_update last_updated show_time_prefix=show_time_prefix %}
-    </span>
-{% endif %}

wagtail/contrib/modeladmin/templates/modeladmin/includes/header_with_history.html

@@ -8,7 +8,7 @@
                 <li>
                     {% avatar user=latest_log_entry.user size="small" tooltip=latest_log_entry.user_display_name %}
                     {% trans "Last updated" %}
-                    {% include "wagtailadmin/shared/last_updated.html" with last_updated=latest_log_entry.timestamp show_time_prefix=True %}
+                    {% human_readable_date latest_log_entry.timestamp %}
                 </li>
                 {% if history_url %}
                     <li><a href="{{ history_url }}">{% icon "history" classname="default" %} {% trans "History" %}</a></li>

wagtail/snippets/templates/wagtailsnippets/snippets/_header_with_history.html

@@ -8,7 +8,7 @@
                 <li>
                     {% avatar user=latest_log_entry.user size="small" tooltip=latest_log_entry.user_display_name %}
                     {% trans "Last updated" %}
-                    {% include "wagtailadmin/shared/last_updated.html" with last_updated=latest_log_entry.timestamp show_time_prefix=True %}
+                    {% human_readable_date date=latest_log_entry.timestamp %}
                 </li>
                 {% if history_url %}
                     <li><a href="{{ history_url }}">{% icon "history" classname="default" %} {% trans "History" %}</a></li>