Capabilities option not recognized since c++ rewrite #464

$ ./headsetcontrol -h
HeadsetControl - Control USB gaming headsets on Linux/macOS/Windows
--snip--
OUTPUT
  -o, --output FORMAT               json, yaml, env, standard, short
  -c, --short-output                Compact output (same as -o short)
  -?, --capabilities                List device capabilities
--snip--
$ ./headsetcontrol '-?'
Error: unknown option
$ ./headsetcontrol --capabilities
Error: unknown option