fix: the readme of the example project was wrong

examples/main-demo/README.md

@@ -6,15 +6,20 @@ This is a [Manifest](https://manifest.build) demo project.
 
 In the project directory, you can run:
 
-### `npm manifest`
+```
+npm i
+npm run manifest
+```
 
 Runs the app in the development mode.\
 Open [http://localhost:1111](http://localhost:1111) to view the admin panel in your browser.\
 Open [http://localhost:1111/api](http://localhost:1111/api) to view the REST API documentation in your browser.\
 
 The page will reload when you make changes.
 
-### `npm manifest:seed`
+````
+npm manifest:seed
+```
 
 Seeds dummy data for your entities and properties. This commands deletes the previous data.