[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>

typo3/sysext/t3editor/Resources/Private/tsref.xml

@@ -5855,7 +5855,7 @@ Character that devides the decimals from the rest. Defaults to "."
 ]]></description>
 			<default><![CDATA[.]]></default>
 		</property>
-		<property name="thousand_sep" type="stdWrap">
+		<property name="thousands_sep" type="stdWrap">
 			<description><![CDATA[string / stdWrap
 Character that devides the thousands of the number. Defaults to ",", set an empty value to have no thousands separator.
 ]]></description>