[Feature request] Add help switch to all tasks

[KajinOnd]

Poe shows full documentation of all configured tasks when invoked with poe --help. However, invokingpoe <task> --help results in error.

When dozens of tasks are defined, it's tedious to search for the help of a specific task (yes, can be solved with grep -A).

How to reproduce

• use the enclosed pyproject.txt file (sorry for .txt, GH doesn't accept .toml)
• run poe <task> --help, it crashes with poe ls: error: unrecognized arguments: --help

Desired behaviour

• the help is displayed, something like

Usage: 
  poe ls directory
Options:
  directory           Directory to list [default: .]