* cli: remove help entries for commands removed long ago
/pq and /pq @<name> were removed in #4049 (PQ encryption for contacts
is now automatic); /get stats and /reset stats were removed in #4375
(legacy agent stats). All four were left documented in CLI help, so
typing them fails. Remove the stale entries.
* plans: justify removal of outdated CLI help entries
* plans: drop //get stats mention from CLI help plan
