Ship Kotlin helper functions by default

[vlsi]

Feature summary

There's a value in shipping Kotlin-friendly API by default.

See https://github.com/junit-team/junit5/blob/main/junit-jupiter-api/src/main/kotlin/org/junit/jupiter/api/Assertions.kt

For example, the current SoftAssertions syntax is

SoftAssertions.assertSoftly { softly ->
    // ...
    softly.assertThat(...).isEqualTo(...)
    // ...
    softly.assertAll()
}

The issue is that it is verbose, and the user might fail to call assertAll.

A better variation would be

assertSoftly {
    assertThat(...).isEqualTo(...)
    // no need to call assertAll, it would be automatic
}

That is achievable with a small helper:

    fun assertSoftly(body: SoftAssertions.() -> Unit) =
        SoftAssertions.assertSoftly(body)