gulp-cli/test/fixtures
├─┬ default
│ └─┬ <series>
│   ├── task1
│   └─┬ <parallel>
│     ├── task2
│     └── task3
├── no-desc
├── task1             Description for gulp.task("task1")
│   --flag-of-task1   …Description for flag of task1
├── task2             Description for gulp.task("task2").unwrap()
│   --flag-of-task2   …Description for flag of task2
└── task3             Use gulp.task("task3").description preferentially
    --flag0-of-task3  …Description for flag0 of task3
    --flag1-of-task3  …Use gulp.task("task3").flags preferentially
