Support running custom spec styles

[solonovamax]

Currently, the kotest idea plugin doesn't support custom test styles. It would be nice if at the very least, a run arrow was shown for the custom test style classes.

[sksamuel]

How would it know if you define your own DSL?
Do you have an example of the DSL you're using ?

[solonovamax]

How would it know if you define your own DSL?

You can check if the class subclasses io.kotest.core.spec.Spec or io.kotest.core.spec.DslDriveSpec

Here's an example of a custom DSL:
https://github.com/solo-studios/nyx/blob/master/src/testFixtures/kotlin/ca/solostudios/nyx/kotest/spec/NyxSpec.kt

Usage:
https://github.com/solo-studios/nyx/blob/master/src/test/kotlin/ca/solostudios/nyx/NyxPluginTest.kt
https://github.com/solo-studios/nyx/blob/master/src/functionalTest/kotlin/ca/solostudios/nyx/NyxPluginFunctionalTest.kt