Use @PublishedApi annotation on functions called from plugin-generate…

…d code

Since these functions can be called from other modules, they should have this annotation to satisfy a compiler visibility checker.

Fixes #2703

core/commonMain/src/kotlinx/serialization/internal/Enums.kt

@@ -49,17 +49,15 @@ internal class EnumDescriptor(
     }
 }
 
-@OptIn(ExperimentalSerializationApi::class)
-@InternalSerializationApi
+@PublishedApi
 internal fun <T : Enum<T>> createSimpleEnumSerializer(serialName: String, values: Array<T>): KSerializer<T> {
     return EnumSerializer(serialName, values)
 }
 
 /**
  * The function has a bug (#2121) and should not be used by new (1.8.20+) plugins. It is preserved for backward compatibility with previously compiled enum classes.
  */
-@OptIn(ExperimentalSerializationApi::class)
-@InternalSerializationApi
+@PublishedApi
 internal fun <T : Enum<T>> createMarkedEnumSerializer(
     serialName: String,
     values: Array<T>,
@@ -78,8 +76,7 @@ internal fun <T : Enum<T>> createMarkedEnumSerializer(
     return EnumSerializer(serialName, values, descriptor)
 }
 
-@OptIn(ExperimentalSerializationApi::class)
-@InternalSerializationApi
+@PublishedApi
 internal fun <T : Enum<T>> createAnnotatedEnumSerializer(
     serialName: String,
     values: Array<T>,