[!!!][TASK] Add native type declarations to GU HTML/XML methods

Resolves: #102116
Releases: main
Change-Id: If78eabc7e7a729d04e6501bb3d9ce1fae0c373c0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/80183


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>