Warn if TActual is object for Numeric Comparison

[manfred-brands]

Given code:

[Test]
public void TestFoatsAndDoubles()
{
    object x = 0.0500000007f;
    Assert.That(x, Is.EqualTo(0.05).Within(0.0000001));
}

This boxes the floating point constant into an object to then do a numeric comparison.
The idea is to remove expensive boxing and subsequent unboxing when not needed.

Fixed code ideally should create:

[Test]
public void TestFoatsAndDoubles()
{
    float x = 0.0500000007f;
    Assert.That(x, Is.EqualTo(0.05).Within(0.0000001));
}