Typing problem when using the `example` attribute of the `Path` class

[EwertonDCSilv]

I believe that keeping the restriction to Optional[Dict[str, Any]] makes the use of examples very rigid.

Wouldn't something like Optional[Union[str, Dict[str, Any]]] be more common?

[EwertonDCSilv]

Nor is the typing of documentation examples included.

[EwertonDCSilv]

@tiangolo It would be important to add a step in the release process that checks the typing signature via mypy