remove json references from readme

packages/jest-serializer/README.md

@@ -2,7 +2,7 @@
 
 > DEPRECATED: Use `v8` APIs directly: https://nodejs.org/api/v8.html#serialization-api
 
-Module for serializing and deserializing object into memory and disk. By default, the `v8` implementations are used, but if not present, it defaults to `JSON` implementation. Both serializers have the advantage of being able to serialize `Map`, `Set`, `undefined`, `NaN`, etc, although the JSON one does it through a replacer/reviver.
+Module for serializing and deserializing object into memory and disk. The Node core `v8` implementations are used. This seriializer have the advantage of being able to serialize `Map`, `Set`, `undefined`, `NaN`, etc..
 
 ## Install