[Docs] Add swith_language.md in docs (#2160)

docs/en/index.rst

@@ -36,6 +36,11 @@ You can switch between Chinese and English documents in the lower-left corner of
    deployment/tensorrt_custom_ops.md
    deployment/tensorrt_plugin.md
 
+.. toctree::
+   :caption: Switch Language
+
+   switch_language.md
+
 .. toctree::
    :maxdepth: 2
    :caption: Compatibility

docs/en/switch_language.md

+## <a href='https://mmcv.readthedocs.io/en/latest/'>English</a>
+
+## <a href='https://mmcv.readthedocs.io/zh_CN/latest/'>简体中文</a>

docs/zh_cn/index.rst

@@ -35,6 +35,11 @@
    deployment/tensorrt_plugin.md
    deployment/tensorrt_custom_ops.md
 
+.. toctree::
+   :caption: 语言切换
+
+   switch_language.md
+
 .. toctree::
    :maxdepth: 2
    :caption: 兼容性

docs/zh_cn/switch_language.md

+## <a href='https://mmcv.readthedocs.io/en/latest/'>English</a>
+
+## <a href='https://mmcv.readthedocs.io/zh_CN/latest/'>简体中文</a>