[BUGFIX] Format search word operator

To dynamically use the search word operator
as part of a locallang key, it has to be formatted
(lowercase and no whitespace).

Resolves: #96775
Releases: main, 11.5
Change-Id: I9ded9337a0a14ed0035ca83d887659aa4f246eb0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73341


Tested-by: Jochen <rothjochen@gmail.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Jochen <rothjochen@gmail.com>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Oliver Bartsch <bo@cedev.de>