Update README

Author: huangxiangyao

README.md

@@ -5,8 +5,12 @@
 ## What's this?
 This Visual Studio Extension will display the charset of current document at the right bottom margin of the editor; Click to popup a contextual menu with a list of encodings and choose the encoding that you want to convert the document to.
 
+Multi-targeting:
+- Visual Studio 2022 (17.x)
+- Visual Studio 2019 (16.x)
+
 **NOTES**:
-1. The file's modification status will be changed to dirty, since you'd changed the encoding of the file.
+1. The file's modification status will be changed to `dirty` (aka Modified), since you'd changed the encoding of the file.
 2. UTF-8 as default: When the encoding could be regarded as both UTF-8 and the locale default encoding (e.g. `GB2312`), this app will take it as `UTF-8` instead of the locale default.
 
 ## Screenshots

README.zh.md

@@ -5,8 +5,13 @@
 ## 介绍
 本 Visual Studio 扩展（vsix）在Visual Studio的编辑器边栏的右下角显示文档的编码, 点击后可修改为您指定的编码。
 
-- **保持切换前文件的状态**：若切换到另一编码前，文件状态是未保存状态，则切换后也是未保存状态；若切换前文件不是修改状态，则切换后自动保存。
-- **默认为UTF-8**：当文件编码为本地时，改为UTF-8。
+支持版本：
+- Visual Studio 2022 (17.x)
+- Visual Studio 2019 (16.x)
+
+说明：
+- **文件状态**：若切换到另一编码，则文件状态将被标记为`未保存`状态。
+- **默认编码**：文件编码默认为`UTF-8`，而不是此前的本地默认编码（例如GB2312)。
 
 ## Screenshots