KT-53778 Remove experimental annotations from open ranges

libraries/stdlib/wasm/builtins/kotlin/Char.kt

@@ -73,8 +73,8 @@ public class Char private constructor(private val value: Char) : Comparable<Char
      *
      * If the [other] value is less than or equal to `this` value, then the returned range is empty.
      */
-    @SinceKotlin("1.7")
-    @ExperimentalStdlibApi
+    @SinceKotlin("1.9")
+    @WasExperimental(ExperimentalStdlibApi::class)
     public operator fun rangeUntil(other: Char): CharRange =
         this until other