[TASK] Fix misleading example in #103437 Feature.rst

The site sets example referenced TYPO3-provided sets
that are not yet available, since the respective implementations
(#103034, #103556) have not be merged yet.

Use generic examples to avoid confusion.

Resolves: #103557
Related: #103437
Releases: main
Change-Id: I008d60167a692ec601b89683bf582233b228ab12
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83697


Tested-by: Benjamin Kott <benjamin.kott@outlook.com>
Reviewed-by: Benjamin Kott <benjamin.kott@outlook.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>