Add a note about usage in a precompiled script plugin

see #2301

docs/src/doc/docs/user_guide/gradle/usage.md

@@ -60,6 +60,14 @@ tasks.named("dokkaHtml") {
 }
 ```
 
+!!! note 
+    Dokka extracts the information about sourcesets from the Kotlin Gradle plugin.
+    Therefore, if you are using Dokka in a [precompiled script plugin](https://docs.gradle.org/current/userguide/custom_plugins.html#sec:precompiled_plugins), 
+    you will have to add a depencency to the Kotlin Gradle Plugin as well
+    (`implementation(kotlin("gradle-plugin", "<kotlin-version>"))` resp. `implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:<kotlin-version>")`).
+
+Please 
+
 ## Configuration options
 
 Dokka documents single-platform as well as multi-platform projects. 
@@ -370,4 +378,4 @@ tasks.dokkaHtmlPartial.configure {
 
 Please see the [Dokka Gradle single module example project](https://github.com/Kotlin/dokka/tree/master/examples/gradle/dokka-gradle-example) or [multimodule](https://github.com/Kotlin/dokka/tree/master/examples/gradle/dokka-multimodule-example) for an example.
 
-Also see [generated documentation](https://Kotlin.github.io/dokka/examples/dokka-gradle-example/html) in `HTML` format.
+Also see [generated documentation](https://Kotlin.github.io/dokka/examples/dokka-gradle-example/html) in `HTML` format.