Docs: Restore <https://api.qunitjs.com/config/QUnit.config> redirect

Linked from https://github.com/karma-runner/karma-qunit/tree/v4.2.0#readme

Author: Krinkle

docs/api/config/index.md

@@ -5,6 +5,7 @@ title: QUnit.config
 redirect_from:
   - "/QUnit.config/"
   - "/config/"
+  - "/config/QUnit.config/"
 ---
 
 General configuration options for QUnit.