Use Is.False / Is.True instead of Is.EqualTo

[seanblue]

It would be helpful to have analyzers that suggest converting Is.EqualTo(false) to Is.False and Is.EqualTo(true) to Is.True. It should probably only flag this when using the false/true keywords within Is.EqualTo, not when those values are coming from variables, since the variables could be a design choice to be reused between setup and assertion.

[seanblue]

Similar analyzers could be made for Is.Null, Is.Empty, Is.Default, and Is.Zero. Should I write a new ticket for those or is it better to add those onto this one?

[manfred-brands]

Some of these already exists, see #826 and #828