Merge branch '2.8' into 3.3

* 2.8:
  [2.8] Fix some docblocks
  Escape trailing \ in QuestionHelper autocompletion
  Add "doctrine/annotations" to top-level composer.json
  Remove inapplicable phpdoc comment
  nit: Fix phpdoc inconsistency and unreachable statement

Author: nicolas-grekas

PluralizationRules.php

@@ -71,7 +71,6 @@ public static function get($number, $locale)
             case 'vi':
             case 'zh':
                 return 0;
-                break;
 
             case 'af':
             case 'bn':