style(boilerplate/src/index.ts): correct boilerplate/src/index.ts style

@@ -2,7 +2,7 @@ Component({
   properties: {
     greeting: {
       type: String,
-      value: 'Hello World!'
-    }
-  }
-})
\ No newline at end of file
+      value: 'Hello World!',
+    },
+  },
+});