docs: fix typo in index.html

Fix "unittest" typo in index.html

Author: edysegura

etc/cli.angular.io/index.html

@@ -102,7 +102,7 @@ <h4>ng serve</h4>
 
     <div class="features-list">
         <h4>Test, Lint, Format</h4>
-        <p>Make your code really shine. Run your unittests or your end-to-end tests with the breeze of a command. Execute the official Angular linter and run clang format.</p>
+        <p>Make your code really shine. Run your unit tests or your end-to-end tests with the breeze of a command. Execute the official Angular linter and run clang format.</p>
     </div>