Support Records as Map keys without the need for @JsonDeserialize for @JsonDeserialize(keyUsing=...

[nlisker]

See FasterXML/jackson-future-ideas#62

When records are used as keys of a map, Jackson needs to know how to deserialize them and that requires a custom deserializer class (@JsonDeserialize(keyUsing = Point.Deserializer.class)). For records, the deserialization process is (or should be) known, so a default one can be used automatically, removing the need for an annotation, just like with primitive types.