docs: 更新本地启动文档为cmd.txt

将本地启动文档从txt格式迁移到cmd.txt，并优化命令的格式和可读性

Author: lhy

cmd.txt

@@ -0,0 +1,12 @@
+# install & compile plugin
+npm install
+npm run compile
+
+# build webview
+npm run build-webview
+
+# package
+vsce package
+
+# start debug
+F5