minor #12739 Remove references to the Twig extensions repo (fabpot)

This PR was merged into the 3.4 branch.

Discussion
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Remove references to the Twig extensions repo

The Twig extensions repo is deprecated now. Almost all features have been moved to Twig extra extensions, which are documented in the Twig docs directly (including how to use them from a Symfony app).

Commits
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fcfe1ca Remove references to the Twig extensions repo

Author: javiereguiluz

reference/dic_tags.rst

@@ -1288,42 +1288,6 @@ For information on how to create the actual Twig Extension class, see
 `Twig's documentation`_ on the topic or read the
 :doc:`/templating/twig_extension` article.
 
-Before writing your own extensions, have a look at the
-`Twig official extension repository`_ which already includes several
-useful extensions. For example ``Intl`` and its ``localizeddate`` filter
-that formats a date according to user's locale. These official Twig extensions
-also have to be added as regular services:
-
-.. configuration-block::
-
-    .. code-block:: yaml
-
-        services:
-            Twig\Extensions\IntlExtension:
-                tags: [twig.extension]
-
-    .. code-block:: xml
-
-        <?xml version="1.0" encoding="UTF-8" ?>
-        <container xmlns="http://symfony.com/schema/dic/services"
-            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-            xsi:schemaLocation="http://symfony.com/schema/dic/services
-                https://symfony.com/schema/dic/services/services-1.0.xsd">
-
-            <services>
-                <service id="Twig\Extensions\IntlExtension">
-                    <tag name="twig.extension"/>
-                </service>
-            </services>
-        </container>
-
-    .. code-block:: php
-
-        $container
-            ->register('Twig\Extensions\IntlExtension')
-            ->addTag('twig.extension')
-        ;
-
 twig.loader
 -----------
 
@@ -1404,6 +1368,5 @@ For an example, see the ``DoctrineInitializer`` class inside the Doctrine
 Bridge.
 
 .. _`Twig's documentation`: https://twig.symfony.com/doc/2.x/advanced.html#creating-an-extension
-.. _`Twig official extension repository`: https://github.com/fabpot/Twig-extensions
 .. _`SwiftMailer's Plugin Documentation`: http://swiftmailer.org/docs/plugins.html
 .. _`Twig Loader`: https://twig.symfony.com/doc/2.x/api.html#loaders

reference/twig_reference.rst

@@ -28,12 +28,6 @@ describe these extra features.
     framework. You are probably using some other bundles as well, and
     those might come with their own extensions not covered here.
 
-.. tip::
-
-    The `Twig Extensions repository`_ contains some additional Twig extensions
-    that do not belong to the Twig core, so you might want to have a look at
-    the `Twig Extensions documentation`_.
-
 .. _reference-twig-functions:
 
 Functions
@@ -771,6 +765,4 @@ The available attributes are:
 * ``app.flashes``, returns flash messages from the session
 
 .. _`Twig Reference`: https://twig.symfony.com/doc/2.x/#reference
-.. _`Twig Extensions repository`: https://github.com/twigphp/Twig-extensions
-.. _`Twig Extensions documentation`: http://twig-extensions.readthedocs.io/en/latest/
 .. _`Twig Bridge`: https://github.com/symfony/symfony/tree/master/src/Symfony/Bridge/Twig/Extension