feature #10997 [Form] document the NumberType html5 option (xabbuh)

This PR was merged into the master branch.

Discussion
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[Form] document the NumberType html5 option

see symfony/symfony#30267

Commits
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bc5ac28 document the NumberType html5 option

Author: wouterj

reference/forms/types/number.rst

@@ -12,6 +12,7 @@ that you want to use for your number.
 | Rendered as | ``input`` ``text`` field                                             |
 +-------------+----------------------------------------------------------------------+
 | Options     | - `grouping`_                                                        |
+|             | - `html5`_                                                           |
 |             | - `scale`_                                                           |
 |             | - `rounding_mode`_                                                   |
 +-------------+----------------------------------------------------------------------+
@@ -46,6 +47,18 @@ Field Options
 
 .. include:: /reference/forms/types/options/grouping.rst.inc
 
+html5
+~~~~~
+
+**type**: ``boolean`` **default**: ``false``
+
+.. versionadded:: 4.3
+
+    The ``html5`` option was introduced in Symfony 4.3.
+
+If set to ``true``, the HTML input will be rendered as a native HTML5 ``type="number"``
+form.
+
 scale
 ~~~~~