Merge branch '2.8' into 3.2

* 2.8:
  [DI] Remove unused props from the PhpDumper
  [ProxyManager] Cleanup fixtures
  [Debug] HTML-escape array key
  Add some phpdocs for IDE autocompletion and better SCA
  Fixed typo in docblock

ExceptionHandler.php

@@ -386,7 +386,7 @@ EOF;
                 $formattedValue = str_replace("\n", '', $this->escapeHtml(var_export($item[1], true)));
             }
 
-            $result[] = is_int($key) ? $formattedValue : sprintf("'%s' => %s", $key, $formattedValue);
+            $result[] = is_int($key) ? $formattedValue : sprintf("'%s' => %s", $this->escapeHtml($key), $formattedValue);
         }
 
         return implode(', ', $result);