Added notes on coverage of specific drafts

Author: pwall567

_data/validator-libraries-modern.yml

@@ -137,7 +137,10 @@
       license: Apache License 2.0
     - name: json-kotlin-schema
       url: https://github.com/pwall567/json-kotlin-schema
-      notes: Kotlin implementation of JSON Schema
+      notes: |
+        Kotlin implementation of JSON Schema.
+        (Currently supports most of Draft 7; see the README for details.
+        Full compliance with Draft 7 and later drafts in progress.)
       date-draft:
       draft: [7]
       license: MIT