Change Java to Kotlin

Even though this program runs primarily on the JRE, this is based upon data types that were "migrated" towards Kotlin. So these are technically Kotlin datatypes.

README.md

@@ -27,7 +27,7 @@ graph LR;
     end
 
     LI-->P(Parser);
-    P-->D(Java Datatype)
+    P-->D(Kotlin Datatype)
     
     style Convert fill:#e1e1e1,stroke:none
     style LT stroke:#808080,stroke-dasharray: 5 5