[K/N] Deprecate Retain and RetainForTarget annotations

As a part of efforts to stabilize Native stdlib #KT-55765.

kotlin-native/Interop/JsRuntime/src/main/kotlin/jsinterop.kt

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+@file:Suppress("DEPRECATION") // RetainForTarget
+
 package kotlinx.wasm.jsinterop
 
 import kotlin.native.*

kotlin-native/runtime/src/main/kotlin/kotlin/native/Annotations.kt

@@ -40,6 +40,7 @@ public annotation class SymbolName(val name: String)
  */
 @Target(AnnotationTarget.FUNCTION, AnnotationTarget.CLASS)
 @Retention(AnnotationRetention.BINARY)
+@Deprecated("This annotation will be removed in a future release")
 public annotation class Retain
 
 /**
@@ -47,6 +48,7 @@ public annotation class Retain
  */
 @Target(AnnotationTarget.FUNCTION, AnnotationTarget.CLASS)
 @Retention(AnnotationRetention.BINARY)
+@Deprecated("This annotation will be removed in a future release")
 public annotation class RetainForTarget(val target: String)