add iOS and Android availability comment

Author: buenaflor

sentry-kotlin-multiplatform/src/commonMain/kotlin/io/sentry/kotlin/multiplatform/SentryOptions.kt

@@ -67,6 +67,9 @@ public open class SentryOptions {
     /** This variable controls the max attachment size in bytes */
     public var maxAttachmentSize: Long = 20 * 1024 * 1024
 
-    /** Enables or disables the attach view hierarchy feature when an error happened. */
+    /**
+     * Enables or disables the attach view hierarchy feature when an error happened.
+     * This is only available on iOS and Android.
+     */
     public var attachViewHierarchy: Boolean = false
 }