Fix typo (#1672)

Signed-off-by: yhmo <yihua.mo@zilliz.com>

sdk-core/src/main/java/io/milvus/v2/service/vector/request/ranker/RRFRanker.java

@@ -43,8 +43,8 @@ import java.util.Map;
  * You also can declare a rrf ranker by Function
  * CreateCollectionReq.Function rr = CreateCollectionReq.Function.builder()
  * .functionType(FunctionType.RERANK)
- * .param("strategy", "rrf")
- * .param("params", "{\"k\": 60}")
+ * .param("reranker", "rrf")
+ * .param("k", "60")
  * .build();
  */
 public class RRFRanker extends CreateCollectionReq.Function {

sdk-core/src/main/java/io/milvus/v2/service/vector/request/ranker/WeightedRanker.java

@@ -47,8 +47,8 @@ import java.util.Map;
  * You also can declare a weighter ranker by Function
  * CreateCollectionReq.Function rr = CreateCollectionReq.Function.builder()
  * .functionType(FunctionType.RERANK)
- * .param("strategy", "weighted")
- * .param("params", "{\"weights\": [0.4, 0.6]}")
+ * .param("reranker", "weighted")
+ * .param("weights", "[0.4, 0.6]")
  * .build();
  */
 public class WeightedRanker extends CreateCollectionReq.Function {