Merge branch '2.8' into 3.1

* 2.8:
  [Form] Fix typo in doc comment
  [Config] Handle open_basedir restrictions in FileLocator
  [bugfix] [Console] Set `Input::$interactive` to `false` when command is executed with `--quiet` as verbosity level
  Use JSON_UNESCAPED_SLASHES for lint commands output
  Fixed collapsed ChoiceType options attributes
  Fixed the nullable support for php 7.1 and below

Author: fabpot

Command/YamlLintCommand.php

@@ -157,7 +157,7 @@ private function displayJson(OutputInterface $output, $filesInfo)
             }
         });
 
-        $output->writeln(json_encode($filesInfo, JSON_PRETTY_PRINT));
+        $output->writeln(json_encode($filesInfo, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES));
 
         return min($errors, 1);
     }

Resources/views/Form/choice_attributes.html.php

@@ -1,4 +1,3 @@
-id="<?php echo $view->escape($id) ?>" name="<?php echo $view->escape($full_name) ?>"
 <?php if ($disabled): ?>disabled="disabled" <?php endif ?>
 <?php foreach ($choice_attr as $k => $v): ?>
 <?php if ($v === true): ?>