Fix shouldBeEq function

[juliankotrba]

The passed matcher function of the should function currently only
creates a Result object, but does not do anything with it. To make a
unit test actually fail, a Matcher object should be passed to the
overloaded should function. This commit is changing this behaviour of
the shouldBeEq function.

After applying this fix, the kotlintest test

"shouldBeEq improved" {
      1.shouldBeEq(2, Int.eq())
}

will fail with the following error message:

Expected: 2 but found: 1
java.lang.AssertionError: Expected: 6 but found: 5
at arrow.test.laws.LawKt.shouldBeEqAllNew(Law.kt:31)
...

[juliankotrba]

Hey @nomisRev, it would be nice if you could take a look at this PR, since you are the original author of shouldBeEq :)
Maybe I misunderstood something..

[nomisRev]

@juliankotrba nice catch thanks! 👍

[juliankotrba]

@juliankotrba nice catch thanks! 👍

Thanks for taking your time 🙌