minor #19616 [Form] Fix wrong form name (kikminev)

This PR was submitted for the 7.1 branch but it was merged into the 6.4 branch instead.

Discussion
----------

[Form] Fix wrong form name

<!--

If your pull request fixes a BUG, use the oldest maintained branch that contains
the bug (see https://symfony.com/releases for the list of maintained branches).

If your pull request documents a NEW FEATURE, use the same Symfony branch where
the feature was introduced (and `7.x` for features of unreleased versions).

-->

Commits
-------

c804e76 Fix wrong form name

Author: javiereguiluz

form/dynamic_form_modification.rst

@@ -546,7 +546,7 @@ field according to the current selection in the ``sport`` field:
 .. code-block:: html+twig
 
     {# templates/meetup/create.html.twig #}
-    {{ form_start(form, { attr: { id: 'supply_history_form' } }) }}
+    {{ form_start(form, { attr: { id: 'sport_meetup_form' } }) }}
         {{ form_row(form.sport) }}    {# <select id="meetup_sport" ... #}
         {{ form_row(form.position) }} {# <select id="meetup_position" ... #}
         {# ... #}