anchor.diff:    This may be specified multiple times to subscribe to multiple topics.  If
     not specified at all, then a default subscription to everything is assumed.
   
  -=== Protocol Selection
  +=== Protocol Selection Options
   NOTE: At least one protocol must be selected.
   
   *--bus, --bus0*::
  
positive.code: POSIX style option clustering of single letter options is not supported;
  each option must be presented as a separate argument to the program.
  
  === Generic
  *-h, --help*::
    Get usage help.
  *-V, --version*::
  
negative.code:   This protocol receives survey requests from <<nng_surveyor#,nng_surveyor(7)>>
    version 0 peers, and can send a reply to them.
  
  === Peer Selection Options
  NOTE: At least one peer address must be selected.
  
  TIP: While legacy _nanocat_ only supported one peer, _nng_ can support
  