Rule to check users don't accidentally specify CallerArgumentExpression parameters

[manfred-brands]

To improve messages for failing tests, NUnit4 uses CallerMemberExpresion to convert the actual and constraint parameters into text.

Users used to the old format spec, might accidentally pass in two paramters without realizing that this doesn't work.

Assert.That(actual, Is.EqualTo(expected), "Expected {0}, but got {1}", expected, actual);

In NUnit 4, this should have been specified as:

Assert.That(actual, Is.EqualTo(expected), $"Expected {expected}, but got {actual}");