[DOCS] Adjust Includes.rst.txt after switch to PHP-based rendering

Resolves: #103350
Related: #103304
Releases: main, 12.4, 11.5
Change-Id: I228f946b8bca26b5c334b352ecd48edfd72c620b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83412


Tested-by: Lina Wolf <112@linawolf.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Lina Wolf <112@linawolf.de>