minor #1302 [Docs] Remove double {{ form_start(form) }} (JeroenMoonen)

This PR was merged into the 2.x branch.

Discussion
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[Docs] Remove double {{ form_start(form) }}

| Q             | A
| ------------- | ---
| Bug fix?      |no
| New feature?  |no
| Issues        | Fix
| License       | MIT

Remove double form start in docs.

Commits
-------

db67904 Remove double {{ form_start(form) }}

Author: kbond

src/LiveComponent/doc/index.rst

@@ -1943,8 +1943,6 @@ Override the specific block for comment items:
     {% form_theme form 'components/_form_theme_comment_list.html.twig' %}
 
     <div {{ attributes }}>
-        {{ form_start(form) }}
-
         {{ form_start(form) }}
             {{ form_row(form.title)