[FEATURE] Allow modifying fetched page content (#5110)

* [TASK] Update code snippets

References: TYPO3-Documentation/Changelog-To-Doc#1165
Releases: main, 13.4

* Apply suggestions from code review

Co-authored-by: Stefan Frömken <froemken@gmail.com>

---------

Co-authored-by: Stefan Frömken <froemken@gmail.com>

Documentation/ApiOverview/Events/Events/Frontend/AfterContentHasBeenFetchedEvent.rst

@@ -0,0 +1,34 @@
+..  include:: /Includes.rst.txt
+..  index:: Events; AfterContentHasBeenFetchedEvent
+..  _AfterContentHasBeenFetchedEvent:
+
+===============================
+AfterContentHasBeenFetchedEvent
+===============================
+
+..  versionadded:: 13.4.2 / 14.0
+
+Using the PSR-14 :php:`\TYPO3\CMS\Frontend\Event\AfterContentHasBeenFetchedEvent`,
+it is possible to manipulate the page content, which has been fetched by the
+`page-content data processor <https://docs.typo3.org/permalink/t3tsref:PageContentFetchingProcessor>`_,
+based on the page layout and corresponding columns configuration.
+
+..  _AfterContentHasBeenFetchedEvent-example:
+
+Example
+=======
+
+The event listener class, using the PHP attribute :php:`#[AsEventListener]` for
+registration, removes some of the fetched page content elements based on
+specific field values.
+
+..  literalinclude:: _AfterContentHasBeenFetchedEvent/_MyEventListener.php
+    :language: php
+    :caption: EXT:my_extension/Classes/Frontend/EventListener/MyEventListener.php
+
+..  _AfterContentHasBeenFetchedEvent-api:
+
+API
+===
+
+..  include:: /CodeSnippets/Events/Frontend/AfterContentHasBeenFetchedEvent.rst.txt

Documentation/ApiOverview/Events/Events/Frontend/_AfterContentHasBeenFetchedEvent/_MyEventListener.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace MyVendor\MyExtension\Frontend\EventListener;
+
+use TYPO3\CMS\Core\Attribute\AsEventListener;
+use TYPO3\CMS\Frontend\Event\AfterContentHasBeenFetchedEvent;
+
+final readonly class MyEventListener
+{
+    #[AsEventListener]
+    public function removeFetchedPageContent(AfterContentHasBeenFetchedEvent $event): void
+    {
+        foreach ($event->groupedContent as $columnIdentifier => $column) {
+            foreach ($column['records'] ?? [] as $key => $record) {
+                if ($record->has('parent_field_name') && (int)($record->get('parent_field_name') ?? 0) > 0) {
+                    unset($event->groupedContent[$columnIdentifier]['records'][$key]);
+                }
+            }
+        }
+    }
+}

Documentation/CodeSnippets/Config/Api/Events/EventsFrontend.php

@@ -159,4 +159,10 @@
         'targetFileName' => 'CodeSnippets/Events/Frontend/AfterTypoScriptDeterminedEvent.rst.txt',
         'withCode' => false,
     ],
+    [
+        'action' => 'createPhpClassDocs',
+        'class' => \TYPO3\CMS\Frontend\Event\AfterContentHasBeenFetchedEvent::class,
+        'targetFileName' => 'CodeSnippets/Events/Frontend/AfterContentHasBeenFetchedEvent.rst.txt',
+        'withCode' => false,
+    ],
 ];

Documentation/CodeSnippets/Events/Frontend/AfterContentHasBeenFetchedEvent.rst.txt

@@ -0,0 +1,13 @@
+..  Generated by https://github.com/TYPO3-Documentation/t3docs-codesnippets
+..  php:namespace::  TYPO3\CMS\Frontend\Event
+
+..  php:class:: AfterContentHasBeenFetchedEvent
+
+    Event listeners are able to manipulate fetched page content, which is already grouped by column
+
+    ..  php:attr:: groupedContent
+        :public:
+
+    ..  php:attr:: request
+        :readonly:
+        :public: