Fix broken link (#12387)

* Fix broken link

Link was producing a 404 error as the file no longer exists. Wasn't sure where this intended link used to go so took a guess at a appropriate target.

* Update quick-start.md

docs/tutorial/quick-start.md

@@ -18,5 +18,5 @@ To learn more about Electron, check out the
 
 [first-app]: ./first-app.md
 [processes]: ./application-architecture.md#main-and-renderer-processes
-[readme]: ../README.md
+[readme]: ../