IR: Move annotation @JsExport to common source set in stdlib #KT-35966

libraries/stdlib/common/src/kotlin/JsAnnotationsH.kt

@@ -12,4 +12,36 @@ import kotlin.annotation.AnnotationTarget.*
  */
 @Target(CLASS, FUNCTION, PROPERTY, CONSTRUCTOR, PROPERTY_GETTER, PROPERTY_SETTER)
 @OptionalExpectation
-public expect annotation class JsName(val name: String)
+public expect annotation class JsName(val name: String)
+
+/**
+ * Marks experimental JS export annotations.
+ *
+ * Note that behavior of these annotations will likely be changed in the future.
+ *
+ * Usages of such annotations will be reported as warnings unless an explicit opt-in with
+ * the [OptIn] annotation, e.g. `@OptIn(ExperimentalJsExport::class)`,
+ * or with the `-Xopt-in=kotlin.js.ExperimentalJsExport` compiler option is given.
+ */
+@Suppress("DEPRECATION")
+@Experimental(level = Experimental.Level.WARNING)
+@RequiresOptIn(level = RequiresOptIn.Level.WARNING)
+@MustBeDocumented
+@Retention(AnnotationRetention.BINARY)
+@SinceKotlin("1.4")
+public annotation class ExperimentalJsExport
+
+/**
+ * Exports top-level declaration.
+ *
+ * Compiler exports from the module those top-level declarations that are marked with this annotation.
+ * There is no effect if this annotation is applied to a non-top-level declaration.
+ *
+ * This annotation has effect only on top-level declarations and only in IR-based JS backend.
+ */
+@ExperimentalJsExport
+@Retention(AnnotationRetention.BINARY)
+@Target(CLASS, PROPERTY, FUNCTION, FILE)
+@SinceKotlin("1.4")
+@OptionalExpectation
+public expect annotation class JsExport()