Improve simulator type hints

[alexrudd2]

Solves another 3 mypy errors.

config_types below seemed like a good candidate for using a TypedDict (~equivalent to a struct)


pymodbus/pymodbus/datastore/simulator.py

Lines 110 to 117 in 214c7ed

	self.config_types = {
	Label.type_bits: {
	Label.type: CellType.BITS,
	Label.next: None,
	Label.value: 0,
	Label.action: None,
	Label.method: self.handle_type_bits,
	},

However, I ran into issues:
(1) mypy doesn't support using variables as TypedDict keys: python/mypy#7178. This unfortunate deficiency means TypedDict is not suitable here until mypy improves.
(2) Using type as a key is messy, since it's a "soft keyword". Maybe it would be better to use kind? This should have a benefit beyond mypy.

[janiversen]

That is surely good news, that did not work 1-2 years ago.

Thanks.