docs: contributing windows link be absolute to bun.sh (oven-sh#16127)

Author: RiskyMH

CONTRIBUTING.md

@@ -1,6 +1,6 @@
 Configuring a development environment for Bun can take 10-30 minutes depending on your internet connection and computer speed. You will need ~10GB of free disk space for the repository and build artifacts.
 
-If you are using Windows, please refer to [this guide](/docs/project/building-windows)
+If you are using Windows, please refer to [this guide](https://bun.sh/docs/project/building-windows)
 
 ## Install Dependencies