must be `--eggs` else "error: option --egg not a unique prefix"
must be `--eggs` else "error: option --egg not a unique prefix"

```
> python setup.py clean --egg
Creating entry_points for [OS name - system]: nt - Windows
c:\apps\miniconda3\envs\leo-dev\lib\site-packages\setuptools\dist.py:351: UserWarning: Normalizing '5.8.1-b1-dev1038' to '5.8.1b1.dev1038'
  normalized_version,
usage: setup.py [global_opts] cmd1 [cmd1_opts] [cmd2 [cmd2_opts] ...]
   or: setup.py --help [cmd1 cmd2 ...]
   or: setup.py --help-commands
   or: setup.py cmd --help

error: option --egg not a unique prefix
```
dave-shawley/setupext-janitor