[BUGFIX] Use correct ViewHelper namespace in PHPDoc of SubmitViewHelper

In the PHPDoc's example of SubmitViewHelper a wrong namespace was used.
This adds the correct ViewHelper namespace `f:form.submit`.

Resolves: #89667
Releases: master, 9.5
Change-Id: I7b247ca22527f82eb788119c975d4a46d579a087
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62315


Tested-by: Tomas Norre Mikkelsen <tomasnorre@gmail.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Tomas Norre Mikkelsen <tomasnorre@gmail.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Sybille Peters <sypets@gmx.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>