doc: add contributing section to readme and update build instruction style (#863)

* doc: add bash style

* doc: add code of conduct to readme

Co-authored-by: Your Name <you@example.com>

README.md

@@ -27,6 +27,9 @@
   - [(Tap) Repository 0](https://github.com/N4FA/homebrew-xray)
   - [(Tap) Repository 1](https://github.com/xiruizhao/homebrew-xray)
 
+## Contributing
+[Code Of Conduct](https://github.com/XTLS/Xray-core/blob/main/CODE_OF_CONDUCT.md)
+
 ## Usage
 
 [Xray-examples](https://github.com/XTLS/Xray-examples) / [VLESS-TCP-XTLS-WHATEVER](https://github.com/XTLS/Xray-examples/tree/main/VLESS-TCP-XTLS-WHATEVER)
@@ -71,13 +74,13 @@ This repo relies on the following third-party projects:
 
 ### Windows
 
-```
+```bash
 go build -o xray.exe -trimpath -ldflags "-s -w -buildid=" ./main
 ```
 
 ### Linux / macOS
 
-```
+```bash
 go build -o xray -trimpath -ldflags "-s -w -buildid=" ./main
 ```