Update README.md

Author: jcs090218

README.md

@@ -6,6 +6,13 @@
 
 [![CI](https://github.com/emacs-tree-sitter/treesit-langs/actions/workflows/test.yml/badge.svg)](https://github.com/emacs-tree-sitter/treesit-langs/actions/workflows/test.yml)
 
+## 🖥 Usage
+
+```elisp
+(require 'treesit-langs)
+(treesit-langs-major-mode-setup)
+```
+
 ## 🛠️ Contribute
 
 [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg)](http://makeapullrequest.com)
@@ -18,7 +25,6 @@ clone and make pull requests to this repository. Or you can
 clone the project and establish your own branch of this tool.
 Any methods are welcome!
 
-
 ### 🔬 Development
 
 To run the test locally, you will need the following tools: