Update Readme.md
Use more natural English.
xmake is a cross-platform build utility based on lua.
-The project focuses on making development and building easier and provides many features (.e.g package, install, plugin, macro, action, option, task ...),
-so that any developer can quickly pick it up and enjoy the productivity boost when developing and building project.
+The project focuses on making development and building easier and provides many features (e.g package, install, plugin, macro, action, option, task ...),
+so that any developer can quickly pick it up and enjoy a productivity boost when developing and building projects.
<img src="https://xmake.io/assets/img/index/package_manage.png" width="80%" />
-If you want to known more, please refer to:
+If you want to know more, please refer to:
* [Documents](https://xmake.io/#/home)
* [HomePage](https://xmake.io)
