Memocast 2.1.6

1. 添加 markdown 笔记转脑图，在编辑器中右键即可找到对应选项
2. 实现笔记文件夹的正确排序，暂时还不能自定义排序
3. 添加了字数统计
4. 优化性能
5. 色彩优化

What's Changed

• Update Readme and fix translation by @TankNee in #124
• Bump tar from 6.0.5 to 6.1.6 by @dependabot in #137
• 2.1.6 Mindmap, Directory sort, bug fix and so forth by @TankNee in #138

Full Changelog: v2.1.5...v2.1.6