[DOCS] Add example for `Page Module` PSR-14 events

With #98375 hooks in the `Page Module` has been replaced by
modern PSR-14 events to customize the `Page Module` rendering.

The related PSR-14 events are:

* TYPO3\CMS\Backend\View\Event\IsContentUsedOnPageLayoutEvent
* TYPO3\CMS\Backend\View\Event\ModifyDatabaseQueryForContentEvent
* TYPO3\CMS\Backend\View\Event\PageContentPreviewRenderingEvent

This change adds some basic example how to implement event listener
for these events to the corresponding feature ReST changelog file.

Resolves: #102046
Related: #98375
Releases: main, 12.4
Change-Id: Ie7bdd8f365accc0224c28365da2f54e908520bd2
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/81263


Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Chris Müller <typo3@krue.ml>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Tested-by: Chris Müller <typo3@krue.ml>
Tested-by: Georg Ringer <georg.ringer@gmail.com>

typo3/sysext/core/Documentation/Changelog/12.0/Feature-98375-PSR-14EventsInPageModule.rst

@@ -24,6 +24,157 @@ They are drop-in replacement to the removed hooks:
 * :php:`$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS'][PageLayoutView::class]['modifyQuery']`
 * :php:`$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['cms/layout/class.tx_cms_layout.php']['tt_content_drawItem']`
 
+Example for :php:`IsContentUsedOnPageLayoutEvent`
+-------------------------------------------------
+
+Registration of the event in your extension's :file:`Services.yaml`:
+
+..  code-block:: yaml
+    :caption: EXT:my_extension/Configuration/Services.yaml
+
+      MyVendor\MyExtension\Listener\ContentUsedOnPage:
+        tags:
+          - name: event.listener
+            identifier: 'my-extension/view/content-used-on-page'
+
+The corresponding event listener class:
+
+..  code-block:: php
+    :caption: EXT:my_extension/Classes/Listener/ContentUsedOnPage.php
+
+    <?php
+
+    declare(strict_types=1);
+
+    namespace MyVendor\MyExtension\Listener;
+
+    use TYPO3\CMS\Backend\View\Event\IsContentUsedOnPageLayoutEvent;
+
+    final class ContentUsedOnPage
+    {
+        public function __invoke(IsContentUsedOnPageLayoutEvent $event): void
+        {
+            // Get the current record from the event.
+            $record = $event->getRecord();
+
+            // This code will be your domain logic to indicate if content
+            // should be hidden in the page module.
+            if ((int)($record['colPos'] ?? 0) === 999
+                && !empty($record['tx_myext_content_parent'])
+            ) {
+                // Flag the current element as not used. Set it to true, if you
+                // want to flag it as used and hide it from the page module.
+                $event->setUsed(false);
+            }
+        }
+    }
+
+Example for :php:`ModifyDatabaseQueryForContentEvent`
+-----------------------------------------------------
+
+Registration of the event in your extension's :file:`Services.yaml`:
+
+..  code-block:: yaml
+    :caption: EXT:my_extension/Configuration/Services.yaml
+
+      MyVendor\MyExtension\Listener\ModifyDatabaseQueryForContent:
+        tags:
+          - name: event.listener
+            identifier: 'my-extension/view/modify-database-query-for-content'
+
+The corresponding event listener class:
+
+..  code-block:: php
+    :caption: EXT:my_extension/Classes/Listener/ModifyDatabaseQueryForContent.php
+
+    <?php
+
+    declare(strict_types=1);
+
+    namespace MyVendor\MyExtension\Listener;
+
+    use TYPO3\CMS\Backend\View\Event\ModifyDatabaseQueryForContentEvent;
+    use TYPO3\CMS\Core\Database\Connection;
+
+    final class ModifyDatabaseQueryForContent
+    {
+        public function __invoke(ModifyDatabaseQueryForContentEvent $event): void
+        {
+            // early return if we do not need to react
+            if ($event->getTable() !== 'tt_content') {
+                return;
+            }
+
+            // Retrieve QueryBuilder instance from event
+            $queryBuilder = $event->getQueryBuilder();
+
+            // Add an additional condition to the QueryBuilder for the table
+            // Note: This is only a example, modify the QueryBuilder instance
+            //       here to your needs.
+            $queryBuilder = $queryBuilder->andWhere(
+                $queryBuilder->expr()->neq(
+                    'some_field',
+                    $queryBuilder->createNamedParameter(1, Connection::PARAM_INT)
+                )
+            );
+
+            // set updated QueryBuilder to event
+            $event->setQueryBuilder($queryBuilder);
+        }
+    }
+
+Example :php:`PageContentPreviewRenderingEvent`
+-----------------------------------------------
+
+Registration of the event in your extension's :file:`Services.yaml`:
+
+..  code-block:: yaml
+    :caption: EXT:my_extension/Configuration/Services.yaml
+
+      MyVendor\MyExtension\Listener\PageContentPreviewRendering:
+        tags:
+          - name: event.listener
+            identifier: 'my-extension/view/page-content-preview-rendering'
+
+The corresponding event listener class:
+
+..  code-block:: php
+    :caption: EXT:my_extension/Classes/Listener/PageContentPreviewRendering.php
+
+    <?php
+
+    declare(strict_types=1);
+
+    namespace MyVendor\MyExtension\Listener;
+
+    use TYPO3\CMS\Backend\View\Event\PageContentPreviewRenderingEvent;
+
+    final class PageContentPreviewRendering
+    {
+        public function __invoke(PageContentPreviewRenderingEvent): void
+        {
+            $tableName = $event->getTable();
+            $record = $event->getRecord();
+
+            // early return if we do not need to react
+            if ($event->getTable() !== 'tt_content'
+                || ((string)($record['CType'] ?? '') !== 'my-content-element'
+               ) {
+                return;
+            }
+
+            // Create custom preview content
+            $previewContent = sprintf(
+                '<div class="alert alert-notice">No preview available for %s:%s</div>',
+                $event->getTable(),
+                ($event->getRecord()['uid'] ?? 0)
+            );
+
+            // Set (override) preview content with custom content.
+            $event->setPreviewContent($previewContent);
+        }
+    }
+
 Impact
 ======