units: drop "(Varlink)"

units: drop "(Varlink)"

We generally don't specify the protocol implementation in unit descriptions.

For journald, we have:
  $ git grep Description 'units/*journald*'
  units/systemd-journald-audit.socket:Description=Journal Audit Socket
  units/systemd-journald-dev-log.socket:Description=Journal Socket (/dev/log)
  units/systemd-journald-varlink@.socket:Description=Journal Varlink Socket for Namespace %i
  units/systemd-journald.service.in:Description=Journal Service
  units/systemd-journald.socket:Description=Journal Sockets
  units/systemd-journald@.service.in:Description=Journal Service for Namespace %i
  units/systemd-journald@.socket:Description=Journal Sockets for Namespace %i
so we need to keep "Varlink" in the name. But also use "Sockets" (plural)
for the "main" socket unit, since it opens multiple sockets.