[Doc] fix config class imports (#993)

* fix config class imports

* refine README.md

README.md

@@ -139,6 +139,7 @@ If you don't have cross-language requirements, using this mode will
 have better performance.
 ```java
 import io.fury.*;
+import io.fury.config.*;
 import java.util.*;
 
 public class Example {
@@ -185,6 +186,7 @@ public class Example {
 **Java**
 ```java
 import io.fury.*;
+import io.fury.config.*;
 import java.util.*;
 
 public class ReferenceExample {
@@ -347,7 +349,7 @@ We are still improving our protocols, binary compatibility are not ensured betwe
 it's ensured between minor version only. Please
 `versioning` your data by fury major version if you will upgrade fury in the future, see [how to upgrade fury](https://github.com/alipay/fury/blob/main/docs/guide/java_object_graph_guide.md#upgrade-fury) for further details.
 
-Binary compatibility will be ensured before fury 1.0.
+Binary compatibility will be ensured when fury 1.0 is released.
 
 ## Security
 Static serialization are secure. But dynamic serialization such as fury java/python native serialization supports deserialize unregistered types, which provides more dynamics and flexibility, but also introduce security risks.

docs/guide/java_object_graph_guide.md

@@ -21,6 +21,7 @@ import java.util.List;
 import java.util.Arrays;
 
 import io.fury.*;
+import io.fury.config.*;
 
 public class Example {
   public static void main(String[] args) {
@@ -48,6 +49,7 @@ import java.util.List;
 import java.util.Arrays;
 
 import io.fury.*;
+import io.fury.config.*;
 
 public class Example {
   public static void main(String[] args) {
@@ -73,6 +75,7 @@ import java.util.List;
 import java.util.Arrays;
 
 import io.fury.*;
+import io.fury.config.*;
 
 public class Example {
   // reuse fury.
@@ -250,6 +253,7 @@ Or implement `java.io.Externalizable` for a class.
 
 ```java
 import io.fury.*;
+import io.fury.config.*;
 import io.fury.serializers.BufferObject;
 import io.fury.memory.MemoryBuffer;
 

docs/guide/xlang_object_graph_guide.md

@@ -13,6 +13,7 @@ Common types can be serialized automatically: primitive numeric types, string, b
 
 ```java
 import io.fury.*;
+import io.fury.config.*;
 
 import java.util.*;
 
@@ -104,6 +105,7 @@ Serializing user-defined types needs registering the custom type using the regis
 
 ```java
 import io.fury.*;
+import io.fury.config.*;
 import java.util.*;
 
 public class Example2 {
@@ -295,6 +297,7 @@ Shared reference and circular reference can be serialized automatically, no dupl
 
 ```java
 import io.fury.*;
+import io.fury.config.*;
 import java.util.*;
 
 public class ReferenceExample {
@@ -390,6 +393,7 @@ func main() {
 
 ```java
 import io.fury.*;
+import io.fury.config.*;
 import io.fury.serializers.BufferObject;
 import io.fury.memory.MemoryBuffer;