Update docs about javaSemantics flag (#346)

Author: oguzhanunlu

doc/config.md

@@ -48,3 +48,10 @@ may have been built.
 
 The type for this variable is Map<String, String>. 
 
+* javaSemantics
+
+When set to true, use Java-specific semantics rather than native JavaScript semantics.
+
+For example, if the node type is `number` per JS semantics where the value can be losslesly interpreted as `java.lang.Long`, the validator would use `integer` as the node type instead of `number`. This is useful when schema type is `integer`, since validation would fail otherwise.
+
+For more details, please refer to this [issue](https://github.com/networknt/json-schema-validator/issues/334).