Fix link error in PaddleNLP README. (#5100)

* Fix link error in PaddleNLP README.

* Fix link error in README_en.

PaddleNLP/README.md

@@ -108,7 +108,7 @@ electra = ElectraModel.from_pretrained('chinese-electra-small')
 
 - [Embedding API](./docs/embeddings.md)
 
-- [Metrics API](./docs/embeddings.md)
+- [Metrics API](./docs/metrics.md)
 
 - [Models API](./docs/models.md)
 

PaddleNLP/README_en.md

-English | [简体中文] (./README.md)
+English | [简体中文](./README.md)
 
 <p align="center">
   <img src="./docs/imgs/paddlenlp.png" width="520" height ="100" />
@@ -92,7 +92,7 @@ For more pretrained model selection, please refer to [PretrainedModels](./paddle
 
 - [Embedding API](./docs/embeddings.md)
 
-- [Metrics API](./docs/embeddings.md)
+- [Metrics API](./docs/metrics.md)
 
 - [Models API](./docs/models.md)
 
@@ -112,7 +112,11 @@ Please refer to our official AI Studio account for more interactive tutorials: [
 
 ## Community
 
-Join our QQ Technical Group to
+Join our QQ Technical Group for technical exchange right now! ⬇️
+
+<div align="center">
+  <img src="./docs/imgs/qq.png" width="200" height="200" />
+</div>
 
 ## License