complete: zsh: add missing sub cmd completion candidates

complete: zsh: add missing sub cmd completion candidates

Add missing 'restore' and 'switch' sub commands to zsh completion
candidate output. E.g.

  $ git re<tab>
  rebase    -- forward-port local commits to the updated upstream head
  reset     -- reset current HEAD to the specified state
  restore   -- restore working tree files

  $ git s<tab>
  show      -- show various types of objects
  status    -- show the working tree status
  switch    -- switch branches

Signed-off-by: Terry Moschou <redacted>
Signed-off-by: Junio C Hamano <redacted>