Add small demo image to README.md

Author: Exidex

README.md

@@ -4,14 +4,16 @@
 [![Version](https://img.shields.io/jetbrains/plugin/v/PLUGIN_ID.svg)](https://plugins.jetbrains.com/plugin/PLUGIN_ID)
 [![Downloads](https://img.shields.io/jetbrains/plugin/d/PLUGIN_ID.svg)](https://plugins.jetbrains.com/plugin/PLUGIN_ID)
 
+![demo](images/demo.png)
+
 ## ToDo list
 - [ ] [Publish a plugin manually](https://plugins.jetbrains.com/docs/intellij/publishing-plugin.html?from=IJPluginTemplate) for the first time.
 - [ ] Set the Plugin ID in the above README badges.
 - [ ] Set the [Deployment Token](https://plugins.jetbrains.com/docs/marketplace/plugin-upload.html).
 
 <!-- Plugin description -->
 
-IntelliJ Platform plugin with language support for The KDL Document Language
+IntelliJ Platform plugin with language support for [The KDL Document Language](https://kdl.dev/)
 
 <!-- Plugin description end -->