Hello, thanks for the great project!

I've got a very simple example that doesn't work with mypy:

from pytest_check.context_manager import CheckContextManager


def test_something(check: CheckContextManager) -> None:
    check.equal(1, 2, "oops")

Running this code with mypy strict=true yields:

tests/__init__.py:5: error: "CheckContextManager" has no attribute "equal"  [attr-defined]
        check.equal(1, 2, "oops")

Pycharm also complains:

This was originally reported in #175 regarding pylint, this is a slightly different context with mypy.

This is caused by the dynamic nature of adding in attributes to the CheckContextManager instance:

I can see why you might want to do this dynamically and not have the source of truth be on ContextManager instance, but would you consider adding a context_manager.pyi type stub that denotes these functions do in fact get added to ContextManager? I believe that's the solution for this problem.