  --> [ local path prefix ]/tlm_packets/channel_neither_used_nor_omitted.fpp:5:3
   |
 5 | /   telemetry packets P {
 6 | |
 7 | |     packet P group 0 {
...  |
11 | |   }
   | |___^ invalid telemetry packet set P
   |
   = note: telemetry channel c1.T is neither used nor marked as omitted
   |
  ::: [ local path prefix ]/tlm_packets/channel_neither_used_nor_omitted.fpp:3:3
   |
 3 |     instance c1
   |     ----------- component instance is specified here
   |
  ::: [ local path prefix ]/tlm_packets/instances.fpp:15:3
   |
15 |     telemetry T: U32
   |     ---------------- telemetry channel is specified here

