Merge branch 'fc/stage' into integration

Merge branch 'fc/stage' into integration

* fc/stage:
  completion: update 'git reset' new stage options
  reset: allow --keep with --stage
  reset: add --stage and --work options
  completion: update --staged options
  apply: add --work, --no-work options
  apply: add --stage option
  submodule: add --staged options
  stash: add --stage to pop and apply
  stash: add --stage option to save
  rm: add --staged option
  grep: add --staged option
  diff: document --staged
  stage: add edit command
  Add proper 'stage' command