minor #13880 Typo Testing (zairigimad)

This PR was submitted for the 5.0 branch but it was squashed and merged into the 4.4 branch instead.

Discussion
----------

Typo Testing

same typo

<!--

If your pull request fixes a BUG, use the oldest maintained branch that contains
the bug (see https://symfony.com/releases for the list of maintained branches).

If your pull request documents a NEW FEATURE, use the same Symfony branch where
the feature was introduced (and `master` for features of unreleased versions).

-->

Commits
-------

394867d Typo Testing

Author: javiereguiluz

testing.rst

@@ -148,7 +148,7 @@ utilities used in the functional tests:
 Your First Functional Test
 ~~~~~~~~~~~~~~~~~~~~~~~~~~
 Functional tests are PHP files that typically live in the ``tests/Controller``
-directory for your bundle. If you want to test the pages handled by your
+directory of your application. If you want to test the pages handled by your
 ``PostController`` class, start by creating a new ``PostControllerTest.php``
 file that extends a special ``WebTestCase`` class.