Merge branch '2.3' into 2.7

* 2.3:
  fix container cache key generation
  [Translation] Add resources from fallback locale
  [DependencyInjection] enforce tags to have a name
  [YAML] Refine the return value of Yaml::parse()

Author: fabpot

Yaml.php

@@ -21,10 +21,7 @@
 class Yaml
 {
     /**
-     * Parses YAML into a PHP array.
-     *
-     * The parse method, when supplied with a YAML stream (string or file),
-     * will do its best to convert YAML in a file into a PHP array.
+     * Parses YAML into a PHP value.
      *
      *  Usage:
      *  <code>
@@ -43,7 +40,7 @@ class Yaml
      * @param bool   $objectSupport          True if object support is enabled, false otherwise
      * @param bool   $objectForMap           True if maps should return a stdClass instead of array()
      *
-     * @return array The YAML converted to a PHP array
+     * @return mixed The YAML converted to a PHP value
      *
      * @throws ParseException If the YAML is not valid
      */