  --> [ local path prefix ]/tlm_packets/channel_used_and_omitted.fpp:5:3
   |
 5 | /   telemetry packets P {
 6 | |
 7 | |     packet P group 0 {
 8 | |       c1.T
...  |
12 | |     c1.T
13 | |   }
   | |___^ invalid telemetry packet set P
   |
   = note: telemetry channel c1.T is both used and marked omitted
   |
  ::: [ local path prefix ]/tlm_packets/channel_used_and_omitted.fpp:8:7
   |
 8 |         c1.T
   |         ---- used here
   |
  ::: [ local path prefix ]/tlm_packets/channel_used_and_omitted.fpp:12:5
   |
12 |       c1.T
   |       ---- marked omitted here

