[pilot] `fastlane pilot distribute` is not documented

But CLI returns it as a valid option:
λ fastlane pilot help
[✔] 🚀
[13:18:29]: fastlane detected a Gemfile in the current directory
[13:18:29]: however it seems like you don't use `bundle exec`
[13:18:29]: to launch fastlane faster, please use
[13:18:29]:
[13:18:29]: $ bundle exec fastlane pilot help
[13:18:29]:
[13:18:29]: Get started using a Gemfile for fastlane https://docs.fastlane.tools/getting-started/ios/setup/#use-a-gemfile
  pilot

  The best way to manage your TestFlight testers and builds from your terminal

  Commands: (* default)
    add          Adds new external tester(s) to a specific app (if given). This will also add an existing tester to an app.
    builds       Lists all builds for given application
    distribute   Distribute a previously uploaded binary to Apple TestFlight
    export       Exports all external testers to a CSV file
    find         Find tester(s) (internal or external) by their email address
    help       * Display global or [command] help documentation
    import       Import external testers from a CSV file called testers.csv
    list         Lists all registered testers, both internal and external
    remove       Remove external tester(s) by their email address
    upload       Uploads a new binary to Apple TestFlight

  Global Options:
    --verbose
    -h, --help           Display help documentation
    -v, --version        Display version information

  Author:
    Felix Krause <pilot@krausefx.com>

  Website:
    https://fastlane.tools

  Documentation:
    https://docs.fastlane.tools/actions/pilot/
fastlane / docs

[pilot] `fastlane pilot distribute` is not documented #660
