Add link to VS Code Playwright Extension

I just wrote my first tests and would have had an easier time if this document had pointed me to the VS Code extension. This would be further improved by any VS Code + Playwright ninjas that can add details on how best to set up the playwright.config, etc.

docs/contributors/code/e2e/README.md

@@ -36,6 +36,7 @@ xvfb-run npm run test:e2e
 # Only run webkit tests.
 xvfb-run -- npm run test:e2e -- --project=webkit
 ```
+If you're already editing in VS Code, you may find the [Playwright extension](https://playwright.dev/docs/getting-started-vscode) helpful for running, writing and debugging tests.
 
 ## Best practices