📝 Fix demo instructions in README

Author: Androz2091

README.md

@@ -29,4 +29,4 @@ Discord Data Package Explorer is built with **[Svelte](https://svelte.dev)**, an
 * Install the dependencies using `npm install` or `yarn install`.
 * Start the app using `npm run dev` or `yarn dev`!
 
-> Note: for testing purposes, you may append `?demo` to the URL to use the mocked data.
+> Note: for testing purposes, you may append use [this link](https://ddpe.androz2091.fr/stats/demo) to use the mocked data.