Merge branch '4.4' into 5.0

* 4.4:
  Typo in command name. refs #12785
  Fix build error
  [Mailer] Mentioned the getMessageId() method
  [DI] Documented the lint:container command

Author: OskarStark

components/phpunit_bridge.rst

@@ -311,7 +311,7 @@ Deprecation Notices at Autoloading Time
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 By default, the PHPUnit Bridge uses ``DebugClassLoader`` from the
-:doc:`ErrorHandler component </components/error_handler>`_ to throw deprecation
+:doc:`ErrorHandler component </components/error_handler>` to throw deprecation
 notices at class autoloading time. This can be disabled with the
 ``debug-class-loader`` option.
 

mailer.rst

@@ -266,6 +266,17 @@ provides access to the original message (``getOriginalMessage()``) and to some
 debug information (``getDebug()``) such as the HTTP calls done by the HTTP
 transports, which is useful to debug errors.
 
+.. note::
+
+    Some mailer providers change the ``Message-Id`` when sending the email. The
+    ``getMessageId()`` method from ``SentMessage`` always returns the definitive
+    ID of the message (being the original random ID generated by Symfony or the
+    new ID generated by the mailer provider).
+
+    .. versionadded:: 4.4
+
+        The ``getMessageId()`` method was introduced in Symfony 4.4.
+
 The exceptions related to mailer transports (those which implement
 :class:`Symfony\\Component\\Mailer\\Exception\\TransportException`) also provide
 this debug information via the ``getDebug()`` method.

service_container.rst

@@ -784,6 +784,28 @@ you don't need to do *anything*: the service will be automatically loaded. Then,
 implements ``Twig\Extension\ExtensionInterface``. And thanks to ``autowire``, you can even add
 constructor arguments without any configuration.
 
+Linting Service Definitions
+---------------------------
+
+.. versionadded:: 4.4
+
+    The ``lint:container`` command was introduced in Symfony 4.4.
+
+The ``lint:container`` command checks that the arguments injected into services
+match their type declarations. It's useful to run it before deploying your
+application to production (e.g. in your continuous integration server):
+
+.. code-block:: terminal
+
+    $ php bin/console lint:container
+
+Checking the types of all service arguments whenever the container is compiled
+can hurt performance. That's why this type checking is implemented in a
+:doc:`compiler pass </service_container/compiler_passes>` called
+``CheckTypeDeclarationsPass`` which is disabled by default and enabled only when
+executing the ``lint:container`` command. If you don't mind the performance
+loss, enable the compiler pass in your application.
+
 .. _container-public:
 
 Public Versus Private Services