Update documentation

Author: qwwdfsad

CHANGES.md

@@ -3,8 +3,11 @@
 ## Version 1.3.9
 
 * Support of `CoroutineContext` in `Flow.asPublisher` and similar reactive builders (#2155).
-* Transition to new HMPP publication scheme for multiplatform usages.
 * Kotlin updated to 1.4.0.
+* Transition to new HMPP publication scheme for multiplatform usages:
+    * Artifacts `kotlinx-coroutines-core-common` and `kotlinx-coroutines-core-native` are removed.
+    * For multiplatform usages, it's enough to [depend directly](README.md#multiplatform) on `kotlinx-coroutines-core` in `commonMain` source-set.
+    * The same artifact coordinates can be used to depend on platform-specific artifact in platform-specific source-set.
 
 ## Version 1.3.8
 

README.md

@@ -146,9 +146,14 @@ Make sure that you have either `jcenter()` or `mavenCentral()` in the list of re
 
 Core modules of `kotlinx.coroutines` are also available for 
 [Kotlin/JS](#js) and [Kotlin/Native](#native).
-In common code that should get compiled for different platforms, add dependency to  
-[`kotlinx-coroutines-core-common`](https://search.maven.org/artifact/org.jetbrains.kotlinx/kotlinx-coroutines-core-common/1.3.9/jar)
-(follow the link to get the dependency declaration snippet).
+In common code that should get compiled for different platforms, you can add dependency to `kotlinx-coroutines-core` right to the `commonMain` source set:
+```groovy
+commonMain {
+    dependencies {
+        implementation("org.jetbrains.kotlinx:kotlinx-coroutines-core:1.3.9")
+    }
+}
+```
 
 ### Android