[help] Display custom docstring from functions

Hi. There's a way to use my doc string when running from command line?
This is the default behavior:
```
ERROR: The function received no value for the required argument: uuid
Usage: hc-fail UUID
optional flags: --log | --wait

For detailed information on this command, run:
hc-fail --help
```
I wanna see my doc string help, not the Fire one. This is possible?
i.e.
```
Make a health check fail right away
Parameters
----------
uuid :
uuid from the health check task.
log :
Create a custom log message.
```

首先閱讀 Python Fire 對命令列說明和 docstring 的處理，然後使用包含範例 docstring 的函式重現所示的 hc-fail 輸出。確認是否可以在不變更現有錯誤和使用行為的情況下提供所要求的自訂說明；當函式文件依要求顯示並由測試涵蓋時，即視為完成。

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