Merge branch '2.3' into 2.4

Author: weaverryan

book/security.rst

@@ -20,8 +20,8 @@ perform a certain action.
 .. image:: /images/book/security_authentication_authorization.png
    :align: center
 
-Since the best way to learn is to see an example, start by securing your
-application with HTTP Basic authentication.
+Since the best way to learn is to see an example, just imagine that you want
+to secure your application with HTTP Basic authentication.
 
 .. note::
 

components/routing/hostname_pattern.rst

@@ -183,9 +183,9 @@ instance, if you want to match both ``m.example.com`` and
 
     .. tip::
 
-       Make sure you also include a default option for the ``subdomain``
-       placeholder, otherwise you need to include the subdomains value each time
-       you generate the route.
+       Make sure you also include a default option for the ``domain`` placeholder,
+       otherwise you need to include a domain value each time you generate
+       a URL using the route.
 
     .. configuration-block::
 

contributing/community/releases.rst

@@ -25,7 +25,7 @@ with a development period, followed by a maintenance period.
 Development
 -----------
 
-The first six-month period is divided into two phases:
+The full development period lasts six months and is divided into two phases:
 
 * *Development*: *Four months* to add new features and to enhance existing
   ones;
@@ -126,11 +126,12 @@ This results in very predictable dates and maintenance periods:
 Backward Compatibility
 ----------------------
 
-Our `Backwards Compatibility Promise`_ is very strict and allows developers to
-upgrade with confidence from one minor version of Symfony to the next one.
+Our :doc:`Backwards Compatibility Promise </contributing/code/bc>` is very
+strict and allows developers to upgrade with confidence from one minor version
+of Symfony to the next one.
 
 Whenever keeping backward compatibility is not possible, the feature, the
-enhancement, or the bug fix will be scheduled for the next major version.
+enhancement or the bug fix will be scheduled for the next major version.
 
 .. note::