Merge branch '3.4' into 4.2

* 3.4:
  Backported symfony#10998 to 3.4

Author: javiereguiluz

reference/forms/types/options/grouping.rst.inc

@@ -1,7 +1,7 @@
 grouping
 ~~~~~~~~
 
-**type**: ``integer`` **default**: ``false``
+**type**: ``boolean`` **default**: ``false``
 
 This value is used internally as the ``NumberFormatter::GROUPING_USED``
 value when using PHP's ``NumberFormatter`` class. Its documentation is