code: func (r *printRun) RegisterFieldFlags() {
  	r.Flags.BoolVar(&r.all, "A", false, doc(`
  		Print builds in their entirety.
  		With -json, prints all build fields.
  		Without -json, implies -steps and -p.
  	`))
  	r.Flags.BoolVar(&r.steps, "steps", false, "Print steps")
  	r.Flags.BoolVar(&r.properties, "p", false, "Print input/output properties")
  }
docs: // RegisterFieldFlags registers -A, -steps and -p flags.