swarming: use subcommands.Section

This shows help like
```
Client tool to access a swarming server.

Usage:  swarming [command] [arguments]

Commands:

        task related commands

  cancel        cancel a task
  collect       Waits on a set of Swarming tasks
  reproduce     reproduces a task locally
  request-show  returns properties of a request
  spawn-tasks   Spawns a set of Swarming tasks
  tasks         lists tasks
  trigger       Triggers a Swarming task

        bot related commands

  bots          lists bots
  delete-bots   delete bots
  terminate     terminate a bot

        other commands

  help          prints help about a command
  whoami        prints an email address associated with currently cached token
  login         performs interactive login flow
  logout        removes cached credentials
  version       prints the executable version


Use "swarming help [command]" for more information about a command.
Use "swarming help -advanced" to display all commands.
```

Change-Id: I6f91384cc2772ae9a8ff8555016a627b4334d06e
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/3247471
Auto-Submit: Takuto Ikuta <tikuta@chromium.org>
Commit-Queue: Junji Watanabe <jwata@google.com>
Reviewed-by: Junji Watanabe <jwata@google.com>
1 file changed
tree: e512c730c778ce97292a84e65cf8a0442295fd98
  1. appengine/
  2. auth/
  3. auth_service/
  4. buildbucket/
  5. casviewer/
  6. cipd/
  7. client/
  8. cmdrunner/
  9. common/
  10. config/
  11. cv/
  12. dm/
  13. examples/
  14. gae/
  15. gce/
  16. grpc/
  17. hacks/
  18. hardcoded/
  19. led/
  20. logdog/
  21. luci_notify/
  22. lucicfg/
  23. lucictx/
  24. luciexe/
  25. machine-db/
  26. mailer/
  27. milo/
  28. mmutex/
  29. mp/
  30. resultdb/
  31. scheduler/
  32. scripts/
  33. server/
  34. starlark/
  35. swarming/
  36. tokenserver/
  37. tools/
  38. tumble/
  39. vpython/
  40. web/
  41. .gitallowed
  42. .gitattributes
  43. .golangci.yml
  44. AUTHORS
  45. CONTRIBUTING.md
  46. CONTRIBUTORS
  47. LICENSE
  48. OWNERS
  49. PRESUBMIT.py
  50. README.md
  51. WATCHLISTS
  52. codereview.settings
  53. go.mod
  54. go.sum
  55. tools.go
README.md

luci-go: LUCI services and tools in Go

GoDoc

Installing

LUCI Go code is meant to be worked on from an Chromium infra.git checkout, which enforces packages versions and Go toolchain version. First get fetch via depot_tools.git then run:

fetch infra
cd infra/go
eval `./env.py`
cd src/go.chromium.org/luci

Contributing

Contributing uses the same flow as Chromium contributions.