Add Gradle Kotlin configuration tab

[timtebeek]

What problem are you trying to solve?

Kotlin is slowly becoming the default for Gradle projects, but our generated documentation examples give configuration snippets for Groovy.

Describe the solution you'd like

An additional tab for Gradle configuration using Kotlin, for build.gradle.kts files.

Have you considered any alternatives or workarounds?

Maybe it's possible to use the same syntax for both, as Groovy makes the () optional. But that could then look slightly out of place in Groovy build.gradle files, so maybe best to be explicit and support each with a separate documentation tab.

Additional context

I think the changes might be limited to the plugin id line, but it might be good to check that.