[Java] remove vague desc in drop-in replacement jdk serialization libs (

#1291)

README.md

@@ -25,8 +25,8 @@ https://fury.apache.org
 
 In addition to cross-language serialization, Fury also features at:
 
-- Drop-in replace Java serialization frameworks such as JDK/Kryo/Hessian without modifying any code, but 100x faster. 
-  It can greatly improve the efficiency of high-performance RPC calls, data transfer, and object persistence.
+- Drop-in replace Java serialization frameworks such as JDK/Kryo/Hessian, but 100x faster at most, which can greatly improve 
+ the efficiency of high-performance RPC calls, data transfer, and object persistence.
 - **100% compatible** with JDK serialization API with much faster implementation: supporting JDK `writeObject/readObject/writeReplace/readResolve/readObjectNoData/Externalizable` API. 
 - Supports **Java 8~21**, Java 17+ `record` is supported too.
 - Support [AOT compilation serialization](docs/guide/graalvm_guide.md) for **GraalVM native image**, and no reflection/serialization json config are needed.