Improve types for client

[alexrudd2]

Solve another 9 errors with mypy --check-untyped-defs

[janiversen]

Looks ok, with one small change for you, and a line I need to check before approving

[alexrudd2]

I do wonder why it does not complain on line 225-229, it is exactly the same issue (recv returns bytes)...that just goes to show how (sorry for the expression) how incompetent and dangerous these checkers can be :-)

Actually, the situation is more complicated :)

pymodbus/pymodbus/client/base.py

Lines 401 to 406 in a152762

	def recv(self, size):
	"""Receive data.
	:meta private:
	"""
	return size

does not seem correct.

If I keep adding type hints (mostly bytes), the type checkers eventually find this:

pymodbus/pymodbus/client/serial.py

Lines 230 to 232 in a152762

	def _in_waiting(self):
	"""Return waiting bytes."""
	return getattr(self.socket, "in_waiting") if hasattr(self.socket, "in_waiting") else getattr(self.socket, "inWaiting")()

Quite similar to #2031, but I do not see the full picture yet. Hence not (yet) annotating recv().

new findings.

[janiversen]

The recv() is an old relict, which I thought was removed long time ago....the very old code v2x had that for testing reasons I think.

[janiversen]

The _in_waiting() looks OK to me, but it the linters do not agree......

[janiversen]

You decide when you want to merge this and make more in a new PR

[alexrudd2]

Down to 58!