[TASK] Update documentation

Updated code examples to use namespaced classes.

Resolves: #59352
Releases: 1.1
Change-Id: I9152e63bb66412b520c102528bc60e075d22bee9
Reviewed-on: https://review.typo3.org/30570
Reviewed-by: Francois Suter
Tested-by: Francois Suter