docs(cli-quickstart): remove extra word (#3216)

Author: thomasclaudiushuber

public/docs/ts/latest/cli-quickstart.jade

@@ -287,7 +287,7 @@ table(width="100%")
         Inside `e2e/` live the End-to-End tests. 
         They shouldn't be inside `src/` because e2e tests are really a separate app that
         just so happens to test your main app. 
-        That's why it they even have their own `tsconfig.json`.
+        That's why they even have their own `tsconfig.json`.
   tr
     td <code>node_modules/...</code>
     td