[Documentation] Some small fixes

[xoxai]

Hi there!

There are two things I've found in your description file that doesn't work:

1. In "Manipulating with vacuum robot (example)" section you have an example which using CleanRobot class, but it's not imported anywhere in code. So, need to add something like from weback_unofficial.vacuum import CleanRobot.
2. In CleanRobot constructor you don't need to pass self.client as second argument, it looks like just client need to be here: vacuum = CleanRobot(device_name, client).

Thanks for your work, that's beautiful thing :)