updated JsonDeserializer example (#2192)

* fixed json deserializer example

* correcting the json

* updated per review

* updated per review

* updated per review

Author: deeptimarrivada1

gson/src/main/java/com/google/gson/JsonDeserializer.java

@@ -48,11 +48,13 @@
  * deserializer:</p>
  *
  * <pre>
- * class IdDeserializer implements JsonDeserializer&lt;Id&gt;() {
+ * class IdDeserializer implements JsonDeserializer&lt;Id&gt; {
  *   public Id deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context)
  *       throws JsonParseException {
- *     return new Id((Class)typeOfT, id.getValue());
+ *     long idValue = json.getAsJsonPrimitive().getAsLong();
+ *     return new Id((Class) typeOfT, idValue);
  *   }
+ * }
  * </pre>
  *
  * <p>You will also need to register {@code IdDeserializer} with Gson as follows:</p>

gson/src/main/java/com/google/gson/JsonSerializer.java

@@ -48,7 +48,7 @@
  * serializer:</p>
  *
  * <pre>
- * class IdSerializer implements JsonSerializer&lt;Id&gt;() {
+ * class IdSerializer implements JsonSerializer&lt;Id&gt; {
  *   public JsonElement serialize(Id id, Type typeOfId, JsonSerializationContext context) {
  *     return new JsonPrimitive(id.getValue());
  *   }