Translate README.md to Simplified Chinese (#12596)

* README Translation for Chinese (Simplified)

* update link

* h3->h4

* html refactor

* update model list

* fix

* Add a translation guide

* format

* update

* typo

* Refine wording

README.md

@@ -38,6 +38,10 @@ limitations under the License.
     <a href="https://zenodo.org/badge/latestdoi/155220641"><img src="https://zenodo.org/badge/155220641.svg" alt="DOI"></a>
 </p>
 
+<h4 align="center">
+    <p><b>English</b> | <a href="https://github.com/huggingface/transformers/blob/master/README_zh-hans.md">简体中文</a><p>
+</h4>
+
 <h3 align="center">
     <p>State-of-the-art Natural Language Processing for Jax, PyTorch and TensorFlow</p>
 </h3>