assert: accept values with named types in `InDelta*`, `InEpsilon*` about testify HOT 2 OPEN

@RemiMattheyDoret This proposal looks good. However the existing type switch must be preserved (for speed) and the switch on reflect.Kind must be added in the existing default case (like mentioned in the "Consideration" section).

Also: because this change will allow us to accept typed numbers in InDelta* and InEpsilon*, I think that we must enforce that if the type of the expected value has a non-anonymous type, the actual value must be exactly of that type. So changes in InDelta and InExpsilon are expected too:

if reflect.TypeOf(expected).PkgPath() != "" {
    IsType(t, expected, actual)
}

Both changes must happen at the same time: if we introduce the toFloat change first, the type check applied later would be then a breaking change.

As this change extends the behavior it will have to happen on a minor (not patch) release.

from testify.

Test case: https://go.dev/play/p/lGe4Y-2aBfz

func Test(t *testing.T) {
	type F64 float64

	assert.InDelta(t, F64(1.0), F64(1.0), 0.1) // This should succeed
	assert.InDelta(t, 1.0, F64(1.0), 0.1)      // This should succeed
	assert.InDelta(t, F64(1.0), F64(1.0), 0.1) // This should fail: not the expected type

	assert.InEpsilon(t, F64(1.0), F64(1.0), 0.1) // This should succeed
	assert.InEpsilon(t, 1.0, F64(1.0), 0.1)      // This should succeed
	assert.InEpsilon(t, F64(1.0), F64(1.0), 0.1) // This should fail: not the expected type
}

So far all tests fail with "Parameters must be numerical".

from testify.