move the .api files, to verify there are no changes.

modules/mockk-agent/api-old/readme.md

@@ -1,6 +1,20 @@
 This directory contains the `.api` files from the unmerged mockk subprojects.
-I've included them here for easy comparison with the new `.api` file,
-[mockk-agent.api](../api/mockk-agent.api), to help verify there are no changes since merging
-the subprojects.
+
+During the update, the 3 `mockk-agent` subprojects were merged into one Kotlin Multiplatform 
+subproject. Previously each subproject had a separate `.api` file, but now there is just one -
+[`mockk-agent/api/mockk-agent.api`](../api/mockk-agent.api)
+
+I've include the unmerged files here for easy comparison with the new `.api` file, and merged them 
+together into [`mockk-agent/api-old/mockk-agent.api`](./mockk-agent.api), so it's easy to diff them.
+
+The only change is that one segment is in a different location.
+
+```none
+public final class io/mockk/ValueClassSupportKt {
+	public static final fun boxedClass (Ljava/lang/Object;)Lkotlin/reflect/KClass;
+	public static final fun boxedClass (Lkotlin/reflect/KClass;)Lkotlin/reflect/KClass;
+	public static final fun boxedValue (Ljava/lang/Object;)Ljava/lang/Object;
+}
+```
 
 Delete this directory once the migration has been completed!