minor #5787 Definition Tweaks - see #5314 (weaverryan)

This PR was merged into the 2.3 branch.

Discussion
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Definition Tweaks - see #5314

| Q             | A
| ------------- | ---
| Doc fix?      | yes
| New docs?     | no
| Applies to    | all
| Fixed tickets | n/a

See #5314 - I am quite a novice with the Configuration component :).

Commits
-------

51bc906 Fixes thanks to Stof
4e788e4 fixing build failure
67b8ff2 Tweaks - see #5314

Author: weaverryan

components/config/definition.rst

@@ -212,6 +212,10 @@ Before defining the children of an array node, you can provide options like:
 ``addDefaultsIfNotSet()``
     If any child nodes have default values, use them if explicit values
     haven't been provided.
+``normalizeKeys(false)``
+    If called (with ``false``), keys with dashes are *not* normalized to underscores.
+    It is recommended to use this with prototype nodes where the user will define
+    a key-value map, to avoid an unnecessary transformation.
 
 A basic prototyped array configuration can be defined as follows::
 
@@ -310,6 +314,13 @@ The output configuration will be exactly the same as before. In other words, the
 ``sf_connection`` and ``default`` configuration keys are lost. The reason is that
 the Symfony Config component treats arrays as lists by default.
 
+.. note::
+
+    As of writing this, there is an inconsistency: if only one file provides the
+    configuration in question, the keys (i.e. ``sf_connection`` and ``default``)
+    are *not* lost. But if more than one file provides the configuration, the keys
+    are lost as described above.
+
 In order to maintain the array keys use the ``useAttributeAsKey()`` method::
 
     $node

cookbook/event_dispatcher/event_listener.rst

@@ -223,7 +223,7 @@ Request Events, Checking Types
 A single page can make several requests (one master request, and then multiple
 sub-requests - typically by :ref:`templating-embedding-controller`). For the core
 Symfony events, you might need to check to see if the event is for a "master" request
-or a "sub request":
+or a "sub request"::
 
     // src/AppBundle/EventListener/RequestListener.php
     namespace AppBundle\EventListener;