fdo#85340 - Better tooltip for paragraph spacing buttons

Change-Id: I9bb83df5e7ee9517a8f6f88213fc6951c53593bd
Reviewed-on: https://gerrit.libreoffice.org/12076
Reviewed-by: Adolfo Jayme Barrientos <fitojb@ubuntu.com>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>