Use `__signature__`

[ego-thales]

Hi,

I tried this project for my doc, but realized that it seemed to ignore the __signature__ of objects. Am I right? This is critical as in my case I take great care to provide meaningful signature through a __signature__ property defined in my metaclasses. Without this, the doc simply looks at the class __init__, which is absolutely uninformative in my case.

All the best!