[DOCS] Note about reserved keywords for Extbase arguments ("format")

Extbase reserves a couple of keywords for internal use:

* action
* controller
* format (resolving fluid templates for HTML, json, ...)
* __trustedProperties
* __referrer

The notiation "__" (and "@" for sub-arrays) is indiciative
of being reserved keywords, however action/controller/format
are not.

These are now mentioned specifically in the Fluid ViewHelper
"arguments" parameter, so that they can show up in the
auto-generated documentation.

This should help to prevent integrators and developers from
advertly using an argument like "format" as a custom
variable/property name.

Efforts have been made to document this also here:

https://github.com/TYPO3-Documentation/TYPO3CMS-Reference-CoreApi/pull/4525
https://github.com/TYPO3-Documentation/TYPO3CMS-Exceptions/pull/155

Resolves: #102246
Releases: main, 12.4, 11.5
Change-Id: I55a306aaa0ba783f9202350d198c9fdf08f5a997
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/84673


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>