Jmath

Allow for isolation of unit systems from one another.

Units can now be used as type hints in functions with the `units.annotate` decorator.

See https://jmath.jordanhay.com/jmath.units.html#module-jmath.units.annotation

Please see the blog post [here](https://jordanhay.com/post?id=3610107036356187790).

In summary jmath now allows for maths with units in Python.