Add documentation for kotlin-test-testng artifact

libraries/build-docs.xml

@@ -91,6 +91,7 @@
             <sourceRoot path="kotlin.test/common/src/main/kotlin" platforms="JVM,JS"/>
             <sourceRoot path="kotlin.test/jvm/src/main/kotlin" platforms="JVM"/>
             <sourceRoot path="kotlin.test/junit/src/main/kotlin" platforms="JVM"/>
+            <sourceRoot path="kotlin.test/testng/src/main/kotlin" platforms="JVM"/>
             <sourceRoot path="kotlin.test/js/src/main/kotlin" platforms="JS"/>
 
             <sourcelink path=".." url="http://github.com/JetBrains/kotlin/blob/${github.revision}" linesuffix="#L"/>

libraries/kotlin.test/Module.md

@@ -17,6 +17,8 @@ The library consists of the modules:
 - `kotlin-test` – a JVM implementation of assertions from `kotlin-test-common`;
 - `kotlin-test-junit` – provides an implementation of [Asserter] on top of JUnit
   and maps the test annotations from `kotlin-test-annotations-common` to JUnit test annotations;
+- `kotlin-test-testng` – provides an implementation of [Asserter] on top of TestNG
+  and maps the test annotations from `kotlin-test-annotations-common` to TestNG test annotations;
 - `kotlin-test-js` – a JS implementation of common test assertions and annotations 
   with the out-of-the-box support for [Jasmine](https://jasmine.github.io/), [Mocha](https://mochajs.org/), 
   and [Jest](https://facebook.github.io/jest/) testing frameworks, and an experimental way to plug in