Merge branch '4.4' into 5.3

* 4.4:
  Update unit_testing.rst
  Update extension.rst
  Fixed email link issue

Author: wouterj

bundles/extension.rst

@@ -34,7 +34,7 @@ This is how the extension of an AcmeHelloBundle should look like::
     namespace Acme\HelloBundle\DependencyInjection;
 
     use Symfony\Component\DependencyInjection\ContainerBuilder;
-    use Symfony\Component\DependencyInjection\Extension\Extension;
+    use Symfony\Component\HttpKernel\DependencyInjection\Extension;
 
     class AcmeHelloExtension extends Extension
     {

contributing/code_of_conduct/care_team.rst

@@ -21,7 +21,7 @@ Members
 
 Here are all the members of the CARE team (in alphabetic order). You can contact
 any of them directly using the contact details below or you can also contact all
-of them at once by emailing **care@symfony.com**:
+of them at once by emailing ** care@symfony.com **.
 
 * **Timo Bakx**
 

create_framework/unit_testing.rst

@@ -8,8 +8,13 @@ on it will exhibit the same bugs. The good news is that whenever you fix a
 bug, you are fixing a bunch of applications too.
 
 Today's mission is to write unit tests for the framework we have created by
-using `PHPUnit`_. Create a PHPUnit configuration file in
-``example.com/phpunit.xml.dist``:
+using `PHPUnit`_. At first, install PHPUnit as a development dependency:
+
+.. code-block:: terminal
+
+    $ composer require --dev phpunit/phpunit
+
+Then, create a PHPUnit configuration file in ``example.com/phpunit.xml.dist``:
 
 .. code-block:: xml