comment about why we're using xvfb

.github/workflows/test.yml

@@ -18,6 +18,8 @@ jobs:
       - name: Install dependencies
         run: npm ci
       - name: Test
+        # VSCode tests require the app's window to be opened, so we use xvfb to give the runner a display
+        # (https://code.visualstudio.com/api/working-with-extensions/continuous-integration#github-actions)
         uses: coactions/setup-xvfb@v1
         with:
           run: npm run test