Add information about importing run configuration types to the wiki

[Thunderforge]

The wiki page documenting the plugin DSL does not mention that you need to import stuff in order to get JUnit and other types. I was stuck for quite a while until I happened to come across this comment that said that I needed to add this to my build.gradle file:

import org.jetbrains.gradle.ext.*

If information about that could be added to the Wiki, I would be obliged.

[sschuberth]

Thanks for this! I was trying

idea.project.settings {
    runConfigurations {
        defaults(JUnit) {
            vmParameters = '-Dkotlintest.assertions.multi-line-diff=simple'
        }
    }
}

which resulted in the odd error

Cannot create a RunConfiguration named 'JUnit' because this container does not support creating elements by name alone. Please specify which subtype of RunConfiguration to create. Known subtypes are: Application, JUnit, Remote, TestNG

until I added import org.jetbrains.gradle.ext.*.

[ant-druha]

Same case here.