feat: Also simplify Is.EqualTo(0) to Is.Zero

[mikkelbu]

Fixes #824

[manfred-brands]

@mikkelbu I didn't do this because Is.EqualTo(0) is no longer the same as Is.Zero.
The first returns an EqualNumericConstraint<int> and the second EqualConstraint.

Although I think it isn't that relevant for this case, except it allows Is.Zero.IgnoreCase.

On option would be for Is.Zero to return EqualNumericContraint<double>.

Should we also detected other zero values such as 0.0, 0.0f, 0L, etc.

[manfred-brands]

Suggest not to switch on both, but treat the numeric part different. Which allow checking some more 0 values.

[mikkelbu]

@mikkelbu I didn't do this because Is.EqualTo(0) is no longer the same as Is.Zero. The first returns an EqualNumericConstraint<int> and the second EqualConstraint.

Ahh. I didn't consider this - I thought it was an oversight in the PR

Although I think it isn't that relevant for this case, except it allows Is.Zero.IgnoreCase.
On option would be for Is.Zero to return EqualNumericContraint<double>.

I think this makes sense. It could break somebody, but only people that have some odd/wrong constraints (unless I'm overlooking something)

Should we also detected other zero values such as 0.0, 0.0f, 0L, etc.

Yes - I'll update the PR with your suggestion