Exit sounds terminal, so steal Firefox's Find bar tooltip text

Change-Id: I3e16f1ebafe5f497643abda3b1dbfdfeaebb60af
Reviewed-on: https://gerrit.libreoffice.org/8027
Reviewed-by: Samuel Mehrbrodt <s.mehrbrodt@gmail.com>
Reviewed-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>
Tested-by: Björn Michaelsen <bjoern.michaelsen@canonical.com>