[BUGFIX] Rename sub-property thousand_sep of numberFormat

The auto-complete feature of the TS-Editor
suggests a nun existing property thousand_sep.
Its correct name is thousands_sep.

Resolves: #84455
Releases: master,8.7
Change-Id: Id4854a3092de1383181003088e81d6a876142c9d
Reviewed-on: https://review.typo3.org/56336


Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>