Jobs with requires but no run have no help

[lordmauve]

Description

I have a job test defined thus

[tool.thx.jobs.test]
# A shortcut to run both pytest and mypy
requires = ["pytest", "mypy"]

This works as expected functionally, and in thx list, but thx --help describes this as "Run ``" which is incorrect.

$ thx --help
Usage: thx [OPTIONS] COMMAND1 [ARGS]... [COMMAND2 [ARGS]...]...

  Fast command runner for Python projects.

Options:
  --benchmark                 Enable benchmarking
  --debug                     Enable debug output
  --clean                     Clean virtualenvs first
  --live                      Use the "live" Python runtime from thx
  -w, --watch
  -p, --python, --py VERSION  Run commands on a specific python version
  -V, --version               Show the version and exit.
  --help                      Show this message and exit.

Commands:
  clean        Clean up virtual environments and data created by thx
  dump-config
  list         List available commands and exit.
  
  pytest       Run `pytest`
  mypy         Run `mypy`
  test         Run ``
  ruff         Run `ruff format; ruff check --fix`
  lint         Run `ruff format --check; ruff check`
  pip-compile  Run `pip-compile -o requirements-dev.txt --extra dev...
  git-clean    Run `git clean -fdX`

Details

• OS: Linux
• Python version: 3.12
• thx version: 0.6.0
• Can you repro on main? Yes
• Can you repro in a clean virtualenv? Yes