[TASK] Documentation links to invalid URL

The link must be prefixed with www, else the request will just show
an error.

Releases: master, 9.5, 8.7
Resolves: #88044
Change-Id: I2a7e5f34a741e92fdc1174d8be73204c19c197eb
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/60355


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Björn Jacob <bjoern.jacob@tritum.de>
Tested-by: Riccardo De Contardi <erredeco@gmail.com>
Tested-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Riccardo De Contardi <erredeco@gmail.com>
Reviewed-by: Richard Haeser <richard@maxserv.com>