feat: add Kotlin intermediate tour properties

Author: sarahhaggarty

docs/kr.tree

@@ -17,6 +17,7 @@
         <toc-element hidden="true" topic="kotlin-tour-intermediate-classes-interfaces.md"/>
 		<toc-element hidden="true" topic="kotlin-tour-intermediate-objects.md"/>
 		<toc-element hidden="true" topic="kotlin-tour-intermediate-open-special-classes.md"/>
+        <toc-element hidden="true" topic="kotlin-tour-intermediate-properties.md"/>
 	</toc-element>
 	<toc-element toc-title="Kotlin overview">
 		<toc-element topic="multiplatform.topic"/>