bug #3468 enclose YAML string with double quotes to fix syntax highli…

…ghting (xabbuh)

This PR was merged into the 2.3 branch.

Discussion
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enclose YAML string with double quotes to fix syntax highlighting

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | #1886

as mentioned by @ifdattic in #3467

Commits
-------

24be690 enclose YAML string with double quotes to fix syntax highlighting

cookbook/routing/service_container_parameters.rst

@@ -18,16 +18,17 @@ inside your routing configuration:
 
     .. code-block:: yaml
 
+        # app/config/routing.yml
         contact:
             path:     /{_locale}/contact
             defaults: { _controller: AcmeDemoBundle:Main:contact }
             requirements:
-                _locale: %acme_demo.locales%
+                _locale: "%acme_demo.locales%"
 
     .. code-block:: xml
 
+        <!-- app/config/routing.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
-
         <routes xmlns="http://symfony.com/schema/routing"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://symfony.com/schema/routing http://symfony.com/schema/routing/routing-1.0.xsd">
@@ -40,6 +41,7 @@ inside your routing configuration:
 
     .. code-block:: php
 
+        // app/config/routing.php
         use Symfony\Component\Routing\RouteCollection;
         use Symfony\Component\Routing\Route;
 
@@ -82,14 +84,15 @@ path):
 
     .. code-block:: yaml
 
+        # app/config/routing.yml
         some_route:
             path:     /%acme_demo.route_prefix%/contact
             defaults: { _controller: AcmeDemoBundle:Main:contact }
 
     .. code-block:: xml
 
+        <!-- app/config/routing.xml -->
         <?xml version="1.0" encoding="UTF-8" ?>
-
         <routes xmlns="http://symfony.com/schema/routing"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://symfony.com/schema/routing http://symfony.com/schema/routing/routing-1.0.xsd">
@@ -101,6 +104,7 @@ path):
 
     .. code-block:: php
 
+        // app/config/routing.php
         use Symfony\Component\Routing\RouteCollection;
         use Symfony\Component\Routing\Route;
 
@@ -116,7 +120,7 @@ path):
     Just like in normal service container configuration files, if you actually
     need a ``%`` in your route, you can escape the percent sign by doubling
     it, e.g. ``/score-50%%``, which would resolve to ``/score-50%``.
-    
+
     However, as the ``%`` characters included in any URL are automatically encoded,
     the resulting URL of this example would be ``/score-50%25`` (``%25`` is the
     result of encoding the ``%`` character).