DEV: Deprecate the plugin (#134)

Author: CvX

README.md

@@ -1,4 +1,7 @@
-### discourse-user-notes
+# discourse-user-notes
+
+> [!IMPORTANT]
+> This plugin has now been bundled into Discourse core. See: https://meta.discourse.org/t/bundling-more-popular-plugins-with-discourse-core/373574
 
 https://meta.discourse.org/t/user-notes-plugin/41026/