[TASK] Update felogin doc with showForgotPassword change

Related: #50138
Releases: 6.2
Change-Id: I98bf8a4eadfae7183d8904956b3adcfdface1e5b
Reviewed-on: https://review.typo3.org/23918
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer