Use -opt-in instead of -Xopt-in in comments and scripts

libraries/stdlib/jdk7/build.gradle

@@ -70,8 +70,8 @@ compileKotlin {
     kotlinOptions.freeCompilerArgs = [
             "-Xallow-kotlin-package",
             "-Xmultifile-parts-inherit",
-            "-Xopt-in=kotlin.RequiresOptIn",
-            "-Xopt-in=kotlin.contracts.ExperimentalContracts",
+            "-opt-in=kotlin.RequiresOptIn",
+            "-opt-in=kotlin.contracts.ExperimentalContracts",
             "-Xsuppress-deprecated-jvm-target-warning",
     ]
     kotlinOptions.moduleName = project.name
@@ -81,10 +81,10 @@ compileTestKotlin {
     kotlinOptions.freeCompilerArgs = [
             "-Xallow-kotlin-package",
             "-Xmulti-platform",
-            "-Xopt-in=kotlin.RequiresOptIn",
-            "-Xopt-in=kotlin.ExperimentalUnsignedTypes",
-            "-Xopt-in=kotlin.ExperimentalStdlibApi",
-            "-Xopt-in=kotlin.io.path.ExperimentalPathApi",
+            "-opt-in=kotlin.RequiresOptIn",
+            "-opt-in=kotlin.ExperimentalUnsignedTypes",
+            "-opt-in=kotlin.ExperimentalStdlibApi",
+            "-opt-in=kotlin.io.path.ExperimentalPathApi",
             "-Xcommon-sources=${fileTree('../test').join(',')}",
             "-Xsuppress-deprecated-jvm-target-warning",
     ]

libraries/stdlib/jdk7/src/kotlin/io/path/ExperimentalPathApi.kt

@@ -15,7 +15,7 @@ import kotlin.annotation.AnnotationTarget.*
  *
  * Any usage of a declaration annotated with `@ExperimentalPathApi` must be accepted either by
  * annotating that usage with the [OptIn] annotation, e.g. `@OptIn(ExperimentalPathApi::class)`,
- * or by using the compiler argument `-Xopt-in=kotlin.io.path.ExperimentalPathApi`.
+ * or by using the compiler argument `-opt-in=kotlin.io.path.ExperimentalPathApi`.
  */
 @RequiresOptIn(level = RequiresOptIn.Level.ERROR)
 @Retention(AnnotationRetention.BINARY)